Merge remote-tracking branch 'origin/master' into flowr

# Conflicts: # app/assets/javascripts/editor/evaluation.js # app/assets/javascripts/editor/participantsupport.js # app/views/exercises/_editor_output.html.slim # config/code_ocean.yml.example # config/routes.rb
2018-11-28 13:14:21 +01:00
parent ebea8da341 5d13ee0e56
commit b9dce854c4
500 changed files with 12187 additions and 3430 deletions
--- a/.babelrc
+++ b/.babelrc
@ -0,0 +1,18 @@
+{
+  "presets": [
+    ["env", {
+      "modules": false,
+      "targets": {
+        "browsers": "> 1%",
+        "uglify": true
+      },
+      "useBuiltIns": true
+    }]
+  ],
+
+  "plugins": [
+    "syntax-dynamic-import",
+    "transform-object-rest-spread",
+    ["transform-class-properties", { "spec": true }]
+  ]
+}
--- a/.gitignore
+++ b/.gitignore
@ -24,3 +24,9 @@
 /.vagrant
 *.iml
 *.DS_Store
+/node_modules
+/public/packs
+/public/packs-test
+/node_modules
+yarn-debug.log*
+.yarn-integrity
--- a/.postcssrc.yml
+++ b/.postcssrc.yml
@ -0,0 +1,3 @@
+plugins:
+  postcss-import: {}
+  postcss-cssnext: {}
--- a/.rubocop.yml
+++ b/.rubocop.yml
@ -1,4 +1,5 @@
 AllCops:
+  TargetRubyVersion: 2.3
  Exclude:
    - bin/*
    - config/application.rb
@ -7,11 +8,12 @@ AllCops:
    - db/schema.rb
    - public/uploads/**/*
    - tmp/**/*
-  RunRailsCops: true
+Rails:
+  Enabled: true
 Metrics/LineLength:
  Enabled: false
 require: rubocop-rspec
 Style/Documentation:
  Enabled: false
-Style/SpaceInsideHashLiteralBraces:
+Layout/SpaceInsideHashLiteralBraces:
  EnforcedStyle: no_space
--- a/.travis.yml
+++ b/.travis.yml
@ -3,12 +3,20 @@ sudo: required
 services:
  - docker

+language: ruby
+rvm:
+  - 2.5.1
+cache:
+  bundler: true
+  yarn: true
+
+env:
+  global:
+    - secure: "DkOGGPCrRgV08KGgav3Bl+keZQqb11TINQRVQS2aeMaYR5GW7Rt9zEcZzhUE0JdKVVOvm4Cclft7BO4OyMd6Cq9XnZkOOHY+Yn8Qv923761SKrRgkGUkO8eeVKMawAA8lS53XGrMZWCP2xaLsLQYq8xzinnE3GqstoZJaHLnqVs="
+
 addons:
-  code_climate:
-    repo_token:
-      secure: "cZoMNjQKB/D7W4B7JDk9PXooy2WCDypu7R4C/Vi0DziZCU9HRwLbdt9aoH5hgHFa7Fe2rHFgflPAAP7h698ozvP0waFtPqLAj+PbEt27LbBDvW8JcvNkKXA0rj5wyTkzuc/0kD+kPB4oDXMak6gZlB9HCJDsa3kdXScQGTVuPdU="
  postgresql: "9.6"
-  firefox: "latest"
+  firefox: "62.0.3"

 before_install:
  - export DISPLAY=:99.0
@ -19,11 +27,17 @@ before_install:
  - docker pull openhpi/co_execenv_python
  - docker pull openhpi/co_execenv_java
  - mkdir ~/geckodriver
-  - wget -O ~/geckodriver/download.tar.gz https://github.com/mozilla/geckodriver/releases/download/v0.18.0/geckodriver-v0.18.0-linux64.tar.gz
+  - wget -O ~/geckodriver/download.tar.gz https://github.com/mozilla/geckodriver/releases/download/v0.23.0/geckodriver-v0.23.0-linux64.tar.gz
  - tar -xvzf ~/geckodriver/download.tar.gz -C ~/geckodriver/
  - rm ~/geckodriver/download.tar.gz
  - chmod +x ~/geckodriver/geckodriver
  - export PATH=~/geckodriver/:$PATH
+  - curl -L https://codeclimate.com/downloads/test-reporter/test-reporter-latest-linux-amd64 > ./cc-test-reporter
+  - chmod +x ./cc-test-reporter
+
+install:
+  - bundle install --jobs=3 --retry=3 --deployment --path=${BUNDLE_PATH:-vendor/bundle}
+  - yarn install

 before_script:
  - cp .rspec.travis .rspec
@ -35,10 +49,9 @@ before_script:
  - cp config/mnemosyne.yml.travis config/mnemosyne.yml
  - psql --command='CREATE DATABASE travis_ci_test;' --username=postgres
  - bundle exec rake db:schema:load RAILS_ENV=test
+  - ./cc-test-reporter before-build

-cache: bundler
-language: ruby
-rvm:
- 2.3.6
-  
-script: bundle exec rspec --color --format documentation --require spec_helper --require rails_helper && bundle exec codeclimate-test-reporter
+script: bundle exec rspec --color --format documentation --require spec_helper --require rails_helper
+
+after_script:
+  - ./cc-test-reporter after-build --exit-code $TRAVIS_TEST_RESULT
--- a/43
+++ b/43
@ -1,53 +1,48 @@
 source 'https://rubygems.org'

-gem 'activerecord-jdbcpostgresql-adapter', platform: :jruby
 gem 'bcrypt'
 gem 'bootstrap-will_paginate'
 gem 'carrierwave'
 gem 'concurrent-ruby'
-gem 'concurrent-ruby-ext', platform: :ruby
-gem 'activerecord-deprecated_finders', require: 'active_record/deprecated_finders'
 gem 'docker-api', require: 'docker'
 gem 'factory_bot_rails'
 gem 'forgery'
 gem 'highline'
 gem 'jbuilder'
 gem 'jquery-rails'
-gem 'jquery-turbolinks'
-gem 'ims-lti', '1.1.10' # version 1.1.13 will crash, because @provider.valid_request?(request) on lti.rb line 89 will return false.
+gem 'ims-lti', '< 2.0.0'
 gem 'kramdown'
 gem 'newrelic_rpm'
-gem 'pg', '< 1.0', platform: :ruby
+gem 'pg'
 gem 'pry-byebug'
 gem 'puma'
 gem 'pundit'
-gem 'rails', '4.2.10'
+gem 'rails', '5.2.1'
 gem 'rails-i18n'
 gem 'ransack'
 gem 'rubytree'
-gem 'sass-rails', '>= 5.0.7'
-gem 'sdoc', group: :doc
+gem 'sass-rails'
 gem 'slim-rails'
-gem 'bootstrap_pagedown', '>= 1.1.0'
-gem 'pagedown-rails'
+gem 'pagedown-bootstrap-rails'
 gem 'sorcery'
-gem 'thread_safe'
-gem 'turbolinks', '< 5.0.0' # newer versions prevent loading ACE if the page containing is not accessed directly / refreshed
+gem 'turbolinks'
 gem 'uglifier'
-gem 'will_paginate'
-gem 'tubesock'
+gem 'tubesock', git: 'https://github.com/gosukiwi/tubesock', branch: 'patch-1' # Switch to a fork which is compatible with Rails 5
 gem 'faye-websocket'
-gem 'eventmachine', '1.0.9.1' # explicitly added, this is used by faye-websocket, version 1.2.5 still has an error in eventmachine.rb:202: [BUG] Segmentation fault, which is not yet fixed and causes the whole ruby process to crash
+gem 'eventmachine', '1.0.9.1' # explicitly added, this is used by faye-websocket, newer versions might crash or
 gem 'nokogiri'
-gem 'd3-rails', '~>4.0'
+gem 'd3-rails'
+gem 'webpacker'
 gem 'rest-client'
 gem 'rubyzip'
-gem 'mnemosyne-ruby', '~> 1.0'
+gem 'mnemosyne-ruby'
 gem 'whenever', require: false

 group :development, :staging do
-  gem 'better_errors', platform: :ruby
-  gem 'binding_of_caller', platform: :ruby
+  gem 'bootsnap', require: false
+  gem 'listen'
+  gem 'better_errors'
+  gem 'binding_of_caller'
  gem 'capistrano'
  gem 'capistrano3-puma'
  gem 'capistrano-rails'
@ -56,23 +51,21 @@ group :development, :staging do
  gem 'rack-mini-profiler'
  gem 'rubocop', require: false
  gem 'rubocop-rspec'
-  gem 'web-console', platform: :ruby
+  gem 'web-console'
 end

 group :development, :test, :staging do
-  gem 'byebug', platform: :ruby
  gem 'spring'
 end

 group :test do
+  gem 'rails-controller-testing'
  gem 'autotest-rails'
  gem 'capybara'
-  gem 'capybara-selenium', '>= 0.0.6'
+  gem 'selenium-webdriver'
  gem 'headless'
-  gem 'codeclimate-test-reporter', require: false
  gem 'database_cleaner'
  gem 'nyan-cat-formatter'
-  gem 'rake'
  gem 'rspec-autotest'
  gem 'rspec-rails'
  gem 'simplecov', require: false
--- a/Gemfile.lock
+++ b/Gemfile.lock
@ -1,75 +1,91 @@
+GIT
+  remote: https://github.com/gosukiwi/tubesock
+  revision: 86a5ca4f7d3c3a7b9a727ad91df3b9b4912eda39
+  branch: patch-1
+  specs:
+    tubesock (0.2.7)
+      rack (>= 1.5.0)
+      websocket (>= 1.1.0)
+
 GEM
  remote: https://rubygems.org/
  specs:
    ZenTest (4.11.1)
-    actionmailer (4.2.10)
-      actionpack (= 4.2.10)
-      actionview (= 4.2.10)
-      activejob (= 4.2.10)
+    actioncable (5.2.1)
+      actionpack (= 5.2.1)
+      nio4r (~> 2.0)
+      websocket-driver (>= 0.6.1)
+    actionmailer (5.2.1)
+      actionpack (= 5.2.1)
+      actionview (= 5.2.1)
+      activejob (= 5.2.1)
      mail (~> 2.5, >= 2.5.4)
-      rails-dom-testing (~> 1.0, >= 1.0.5)
-    actionpack (4.2.10)
-      actionview (= 4.2.10)
-      activesupport (= 4.2.10)
-      rack (~> 1.6)
-      rack-test (~> 0.6.2)
-      rails-dom-testing (~> 1.0, >= 1.0.5)
+      rails-dom-testing (~> 2.0)
+    actionpack (5.2.1)
+      actionview (= 5.2.1)
+      activesupport (= 5.2.1)
+      rack (~> 2.0)
+      rack-test (>= 0.6.3)
+      rails-dom-testing (~> 2.0)
      rails-html-sanitizer (~> 1.0, >= 1.0.2)
-    actionview (4.2.10)
-      activesupport (= 4.2.10)
+    actionview (5.2.1)
+      activesupport (= 5.2.1)
      builder (~> 3.1)
-      erubis (~> 2.7.0)
-      rails-dom-testing (~> 1.0, >= 1.0.5)
+      erubi (~> 1.4)
+      rails-dom-testing (~> 2.0)
      rails-html-sanitizer (~> 1.0, >= 1.0.3)
-    activejob (4.2.10)
-      activesupport (= 4.2.10)
-      globalid (>= 0.3.0)
-    activemodel (4.2.10)
-      activesupport (= 4.2.10)
-      builder (~> 3.1)
-    activerecord (4.2.10)
-      activemodel (= 4.2.10)
-      activesupport (= 4.2.10)
-      arel (~> 6.0)
-    activerecord-deprecated_finders (1.0.4)
-    activesupport (4.2.10)
-      i18n (~> 0.7)
+    activejob (5.2.1)
+      activesupport (= 5.2.1)
+      globalid (>= 0.3.6)
+    activemodel (5.2.1)
+      activesupport (= 5.2.1)
+    activerecord (5.2.1)
+      activemodel (= 5.2.1)
+      activesupport (= 5.2.1)
+      arel (>= 9.0)
+    activestorage (5.2.1)
+      actionpack (= 5.2.1)
+      activerecord (= 5.2.1)
+      marcel (~> 0.3.1)
+    activesupport (5.2.1)
+      concurrent-ruby (~> 1.0, >= 1.0.2)
+      i18n (>= 0.7, < 2)
      minitest (~> 5.1)
-      thread_safe (~> 0.3, >= 0.3.4)
      tzinfo (~> 1.1)
    addressable (2.5.2)
      public_suffix (>= 2.0.2, < 4.0)
-    airbrussh (1.3.0)
+    airbrussh (1.3.1)
      sshkit (>= 1.6.1, != 1.7.0)
    amq-protocol (2.3.0)
-    arel (6.0.4)
+    arel (9.0.0)
    ast (2.4.0)
    autotest-rails (4.2.1)
      ZenTest (~> 4.5)
-    bcrypt (3.1.11)
-    better_errors (2.4.0)
+    bcrypt (3.1.12)
+    better_errors (2.5.0)
      coderay (>= 1.0.0)
      erubi (>= 1.0.0)
      rack (>= 0.9.0)
+    bindex (0.5.0)
    binding_of_caller (0.8.0)
      debug_inspector (>= 0.0.1)
+    bootsnap (1.3.2)
+      msgpack (~> 1.0)
    bootstrap-will_paginate (1.0.0)
      will_paginate
-    bootstrap_pagedown (1.1.0)
-      rails (>= 3.2)
    builder (3.2.3)
-    bunny (2.11.0)
-      amq-protocol (~> 2.3.0)
-    byebug (10.0.0)
-    capistrano (3.10.1)
+    bunny (2.12.0)
+      amq-protocol (~> 2.3, >= 2.3.0)
+    byebug (10.0.2)
+    capistrano (3.11.0)
      airbrussh (>= 1.0.0)
      i18n
      rake (>= 10.0.0)
      sshkit (>= 1.9.0)
-    capistrano-bundler (1.3.0)
+    capistrano-bundler (1.4.0)
      capistrano (~> 3.1)
      sshkit (~> 1.2)
-    capistrano-rails (1.3.1)
+    capistrano-rails (1.4.0)
      capistrano (~> 3.1)
      capistrano-bundler (~> 1.1)
    capistrano-rvm (0.1.2)
@ -81,59 +97,45 @@ GEM
      capistrano (~> 3.7)
      capistrano-bundler
      puma (~> 3.4)
-    capybara (3.3.1)
+    capybara (3.10.1)
      addressable
      mini_mime (>= 0.1.3)
      nokogiri (~> 1.8)
      rack (>= 1.6.0)
      rack-test (>= 0.6.3)
-      xpath (~> 3.1)
-    capybara-selenium (0.0.6)
-      capybara
-      selenium-webdriver
-    carrierwave (1.2.2)
+      regexp_parser (~> 1.2)
+      xpath (~> 3.2)
+    carrierwave (1.2.3)
      activemodel (>= 4.0.0)
      activesupport (>= 4.0.0)
      mime-types (>= 1.16)
    childprocess (0.9.0)
      ffi (~> 1.0, >= 1.0.11)
    chronic (0.10.2)
-    codeclimate-test-reporter (1.0.7)
-      simplecov
    coderay (1.1.2)
-    coffee-rails (4.2.2)
-      coffee-script (>= 2.2.0)
-      railties (>= 4.0.0)
-    coffee-script (2.4.1)
-      coffee-script-source
-      execjs
-    coffee-script-source (1.12.2)
-    concurrent-ruby (1.0.5)
-    concurrent-ruby-ext (1.0.5)
-      concurrent-ruby (= 1.0.5)
+    concurrent-ruby (1.1.2)
    crass (1.0.4)
-    d3-rails (4.13.0)
+    d3-rails (5.7.0)
      railties (>= 3.1)
-    database_cleaner (1.6.2)
+    database_cleaner (1.7.0)
    debug_inspector (0.0.3)
    diff-lcs (1.3)
-    docile (1.1.5)
-    docker-api (1.34.1)
+    docile (1.3.1)
+    docker-api (1.34.2)
      excon (>= 0.47.0)
      multi_json
-    domain_name (0.5.20170404)
+    domain_name (0.5.20180417)
      unf (>= 0.0.5, < 1.0.0)
    erubi (1.7.1)
-    erubis (2.7.0)
    eventmachine (1.0.9.1)
-    excon (0.60.0)
+    excon (0.62.0)
    execjs (2.7.0)
-    factory_bot (4.8.2)
+    factory_bot (4.11.1)
      activesupport (>= 3.0.0)
-    factory_bot_rails (4.8.2)
-      factory_bot (~> 4.8.2)
+    factory_bot_rails (4.11.1)
+      factory_bot (~> 4.11.1)
      railties (>= 3.0.0)
-    faraday (0.12.2)
+    faraday (0.15.3)
      multipart-post (>= 1.2, < 3)
    faye-websocket (0.10.7)
      eventmachine (>= 0.12.0)
@ -143,166 +145,178 @@ GEM
    globalid (0.4.1)
      activesupport (>= 4.2.0)
    headless (2.3.1)
-    highline (1.7.10)
+    highline (2.0.0)
    http-cookie (1.0.3)
      domain_name (~> 0.5)
-    i18n (0.9.5)
+    i18n (1.1.1)
      concurrent-ruby (~> 1.0)
-    ims-lti (1.1.10)
+    ims-lti (1.2.2)
      builder
-      oauth (~> 0.4.5)
-    jbuilder (2.7.0)
+      oauth (>= 0.4.5, < 0.6)
+    jaro_winkler (1.5.1)
+    jbuilder (2.8.0)
      activesupport (>= 4.2.0)
      multi_json (>= 1.2)
-    jquery-rails (4.3.1)
+    jquery-rails (4.3.3)
      rails-dom-testing (>= 1, < 3)
      railties (>= 4.2.0)
      thor (>= 0.14, < 2.0)
-    jquery-turbolinks (2.1.0)
-      railties (>= 3.1.0)
-      turbolinks
    json (2.1.0)
-    jwt (1.5.6)
-    kramdown (1.16.2)
-    loofah (2.2.2)
+    jwt (2.1.0)
+    kramdown (1.17.0)
+    listen (3.1.5)
+      rb-fsevent (~> 0.9, >= 0.9.4)
+      rb-inotify (~> 0.9, >= 0.9.7)
+      ruby_dep (~> 1.2)
+    loofah (2.2.3)
      crass (~> 1.0.2)
      nokogiri (>= 1.5.9)
-    mail (2.7.0)
+    mail (2.7.1)
      mini_mime (>= 0.1.1)
-    method_source (0.9.0)
-    mime-types (3.1)
+    marcel (0.3.3)
+      mimemagic (~> 0.3.2)
+    method_source (0.9.1)
+    mime-types (3.2.2)
      mime-types-data (~> 3.2015)
-    mime-types-data (3.2016.0521)
-    mini_mime (1.0.0)
+    mime-types-data (3.2018.0812)
+    mimemagic (0.3.2)
+    mini_mime (1.0.1)
    mini_portile2 (2.3.0)
    minitest (5.11.3)
    mnemosyne-ruby (1.5.1)
      activesupport (>= 4)
      bunny
+    msgpack (1.2.4)
    multi_json (1.13.1)
    multi_xml (0.6.0)
    multipart-post (2.0.0)
    net-scp (1.2.1)
      net-ssh (>= 2.6.5)
-    net-ssh (4.2.0)
+    net-ssh (5.0.2)
    netrc (0.11.0)
-    newrelic_rpm (4.8.0.341)
-    nokogiri (1.8.3)
+    newrelic_rpm (5.4.0.347)
+    nio4r (2.3.1)
+    nokogiri (1.8.5)
      mini_portile2 (~> 2.3.0)
    nyan-cat-formatter (0.12.0)
      rspec (>= 2.99, >= 2.14.2, < 4)
-    oauth (0.4.7)
-    oauth2 (1.4.0)
-      faraday (>= 0.8, < 0.13)
-      jwt (~> 1.0)
+    oauth (0.5.4)
+    oauth2 (1.4.1)
+      faraday (>= 0.8, < 0.16.0)
+      jwt (>= 1.0, < 3.0)
      multi_json (~> 1.3)
      multi_xml (~> 0.5)
      rack (>= 1.2, < 3)
-    pagedown-rails (1.1.4)
+    pagedown-bootstrap-rails (2.1.4)
      railties (> 3.1)
    parallel (1.12.1)
-    parser (2.5.0.3)
+    parser (2.5.3.0)
      ast (~> 2.4.0)
-    pg (0.21.0)
-    polyamorous (1.3.3)
-      activerecord (>= 3.0)
-    powerpack (0.1.1)
-    pry (0.11.3)
+    pg (1.1.3)
+    powerpack (0.1.2)
+    pry (0.12.0)
      coderay (~> 1.1.0)
      method_source (~> 0.9.0)
    pry-byebug (3.6.0)
      byebug (~> 10.0)
      pry (~> 0.10)
-    public_suffix (3.0.2)
-    puma (3.11.3)
-    pundit (1.1.0)
+    public_suffix (3.0.3)
+    puma (3.12.0)
+    pundit (2.0.0)
      activesupport (>= 3.0.0)
-    rack (1.6.10)
-    rack-mini-profiler (0.10.7)
+    rack (2.0.6)
+    rack-mini-profiler (1.0.0)
      rack (>= 1.2.0)
-    rack-test (0.6.3)
-      rack (>= 1.0)
-    rails (4.2.10)
-      actionmailer (= 4.2.10)
-      actionpack (= 4.2.10)
-      actionview (= 4.2.10)
-      activejob (= 4.2.10)
-      activemodel (= 4.2.10)
-      activerecord (= 4.2.10)
-      activesupport (= 4.2.10)
-      bundler (>= 1.3.0, < 2.0)
-      railties (= 4.2.10)
-      sprockets-rails
-    rails-deprecated_sanitizer (1.0.3)
-      activesupport (>= 4.2.0.alpha)
-    rails-dom-testing (1.0.9)
-      activesupport (>= 4.2.0, < 5.0)
-      nokogiri (~> 1.6)
-      rails-deprecated_sanitizer (>= 1.0.1)
+    rack-proxy (0.6.5)
+      rack
+    rack-test (1.1.0)
+      rack (>= 1.0, < 3)
+    rails (5.2.1)
+      actioncable (= 5.2.1)
+      actionmailer (= 5.2.1)
+      actionpack (= 5.2.1)
+      actionview (= 5.2.1)
+      activejob (= 5.2.1)
+      activemodel (= 5.2.1)
+      activerecord (= 5.2.1)
+      activestorage (= 5.2.1)
+      activesupport (= 5.2.1)
+      bundler (>= 1.3.0)
+      railties (= 5.2.1)
+      sprockets-rails (>= 2.0.0)
+    rails-controller-testing (1.0.2)
+      actionpack (~> 5.x, >= 5.0.1)
+      actionview (~> 5.x, >= 5.0.1)
+      activesupport (~> 5.x)
+    rails-dom-testing (2.0.3)
+      activesupport (>= 4.2.0)
+      nokogiri (>= 1.6)
    rails-html-sanitizer (1.0.4)
      loofah (~> 2.2, >= 2.2.2)
-    rails-i18n (4.0.9)
-      i18n (~> 0.7)
-      railties (~> 4.0)
-    railties (4.2.10)
-      actionpack (= 4.2.10)
-      activesupport (= 4.2.10)
+    rails-i18n (5.1.2)
+      i18n (>= 0.7, < 2)
+      railties (>= 5.0, < 6)
+    railties (5.2.1)
+      actionpack (= 5.2.1)
+      activesupport (= 5.2.1)
+      method_source
      rake (>= 0.8.7)
-      thor (>= 0.18.1, < 2.0)
+      thor (>= 0.19.0, < 2.0)
    rainbow (3.0.0)
    rake (12.3.1)
-    ransack (1.8.7)
-      actionpack (>= 3.0)
-      activerecord (>= 3.0)
-      activesupport (>= 3.0)
+    ransack (2.1.0)
+      actionpack (>= 5.0)
+      activerecord (>= 5.0)
+      activesupport (>= 5.0)
      i18n
-      polyamorous (~> 1.3.2)
    rb-fsevent (0.10.3)
    rb-inotify (0.9.10)
      ffi (>= 0.5.0, < 2)
-    rdoc (6.0.1)
+    regexp_parser (1.2.0)
    rest-client (2.0.2)
      http-cookie (>= 1.0.2, < 2.0)
      mime-types (>= 1.16, < 4.0)
      netrc (~> 0.8)
-    rspec (3.7.0)
-      rspec-core (~> 3.7.0)
-      rspec-expectations (~> 3.7.0)
-      rspec-mocks (~> 3.7.0)
-    rspec-autotest (1.0.0)
+    rspec (3.8.0)
+      rspec-core (~> 3.8.0)
+      rspec-expectations (~> 3.8.0)
+      rspec-mocks (~> 3.8.0)
+    rspec-autotest (1.0.2)
      rspec-core (>= 2.99.0.beta1, < 4.0.0)
-    rspec-core (3.7.1)
-      rspec-support (~> 3.7.0)
-    rspec-expectations (3.7.0)
+    rspec-core (3.8.0)
+      rspec-support (~> 3.8.0)
+    rspec-expectations (3.8.2)
      diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.7.0)
-    rspec-mocks (3.7.0)
+      rspec-support (~> 3.8.0)
+    rspec-mocks (3.8.0)
      diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.7.0)
-    rspec-rails (3.7.2)
+      rspec-support (~> 3.8.0)
+    rspec-rails (3.8.1)
      actionpack (>= 3.0)
      activesupport (>= 3.0)
      railties (>= 3.0)
-      rspec-core (~> 3.7.0)
-      rspec-expectations (~> 3.7.0)
-      rspec-mocks (~> 3.7.0)
-      rspec-support (~> 3.7.0)
-    rspec-support (3.7.1)
-    rubocop (0.53.0)
+      rspec-core (~> 3.8.0)
+      rspec-expectations (~> 3.8.0)
+      rspec-mocks (~> 3.8.0)
+      rspec-support (~> 3.8.0)
+    rspec-support (3.8.0)
+    rubocop (0.60.0)
+      jaro_winkler (~> 1.5.1)
      parallel (~> 1.10)
-      parser (>= 2.5)
+      parser (>= 2.5, != 2.5.1.1)
      powerpack (~> 0.1)
      rainbow (>= 2.2.2, < 4.0)
      ruby-progressbar (~> 1.7)
-      unicode-display_width (~> 1.0, >= 1.0.1)
-    rubocop-rspec (1.24.0)
-      rubocop (>= 0.53.0)
-    ruby-progressbar (1.9.0)
+      unicode-display_width (~> 1.4.0)
+    rubocop-rspec (1.30.1)
+      rubocop (>= 0.60.0)
+    ruby-progressbar (1.10.0)
+    ruby_dep (1.5.0)
    rubytree (1.0.0)
      json (~> 2.1)
      structured_warnings (~> 0.3)
-    rubyzip (1.2.1)
-    sass (3.5.6)
+    rubyzip (1.2.2)
+    sass (3.6.0)
      sass-listen (~> 4.0.0)
    sass-listen (4.0.0)
      rb-fsevent (~> 0.9, >= 0.9.4)
@ -313,24 +327,22 @@ GEM
      sprockets (>= 2.8, < 4.0)
      sprockets-rails (>= 2.0, < 4.0)
      tilt (>= 1.1, < 3)
-    sdoc (1.0.0)
-      rdoc (>= 5.0)
-    selenium-webdriver (3.13.0)
+    selenium-webdriver (3.141.0)
      childprocess (~> 0.5)
-      rubyzip (~> 1.2)
-    simplecov (0.15.1)
-      docile (~> 1.1.0)
+      rubyzip (~> 1.2, >= 1.2.2)
+    simplecov (0.16.1)
+      docile (~> 1.1)
      json (>= 1.8, < 3)
      simplecov-html (~> 0.10.0)
    simplecov-html (0.10.2)
-    slim (3.0.9)
+    slim (4.0.1)
      temple (>= 0.7.6, < 0.9)
-      tilt (>= 1.3.3, < 2.1)
-    slim-rails (3.1.3)
+      tilt (>= 2.0.6, < 2.1)
+    slim-rails (3.2.0)
      actionpack (>= 3.1)
      railties (>= 3.1)
-      slim (~> 3.0)
-    sorcery (0.11.0)
+      slim (>= 3.0, < 5.0)
+    sorcery (0.12.0)
      bcrypt (~> 3.1)
      oauth (~> 0.4, >= 0.4.4)
      oauth2 (~> 1.0, >= 0.8.0)
@ -343,7 +355,7 @@ GEM
      actionpack (>= 4.0)
      activesupport (>= 4.0)
      sprockets (>= 3.0.0)
-    sshkit (1.16.0)
+    sshkit (1.18.0)
      net-scp (>= 1.1.2)
      net-ssh (>= 2.8.0)
    structured_warnings (0.3.0)
@ -351,58 +363,55 @@ GEM
    thor (0.20.0)
    thread_safe (0.3.6)
    tilt (2.0.8)
-    tubesock (0.2.7)
-      rack (>= 1.5.0)
-      websocket (>= 1.1.0)
-    turbolinks (2.5.4)
-      coffee-rails
+    turbolinks (5.2.0)
+      turbolinks-source (~> 5.2)
+    turbolinks-source (5.2.0)
    tzinfo (1.2.5)
      thread_safe (~> 0.1)
-    uglifier (4.1.6)
+    uglifier (4.1.19)
      execjs (>= 0.3.0, < 3)
    unf (0.1.4)
      unf_ext
    unf_ext (0.0.7.5)
-    unicode-display_width (1.3.0)
-    web-console (3.3.0)
-      activemodel (>= 4.2)
-      debug_inspector
+    unicode-display_width (1.4.0)
+    web-console (3.7.0)
+      actionview (>= 5.0)
+      activemodel (>= 5.0)
+      bindex (>= 0.4.0)
+      railties (>= 5.0)
+    webpacker (3.5.5)
+      activesupport (>= 4.2)
+      rack-proxy (>= 0.6.1)
      railties (>= 4.2)
-    websocket (1.2.5)
+    websocket (1.2.8)
    websocket-driver (0.7.0)
      websocket-extensions (>= 0.1.0)
    websocket-extensions (0.1.3)
    whenever (0.10.0)
      chronic (>= 0.6.3)
    will_paginate (3.1.6)
-    xpath (3.1.0)
+    xpath (3.2.0)
      nokogiri (~> 1.8)

 PLATFORMS
  ruby

 DEPENDENCIES
-  activerecord-deprecated_finders
-  activerecord-jdbcpostgresql-adapter
  autotest-rails
  bcrypt
  better_errors
  binding_of_caller
+  bootsnap
  bootstrap-will_paginate
-  bootstrap_pagedown (>= 1.1.0)
-  byebug
  capistrano
  capistrano-rails
  capistrano-rvm
  capistrano-upload-config
  capistrano3-puma
  capybara
-  capybara-selenium (>= 0.0.6)
  carrierwave
-  codeclimate-test-reporter
  concurrent-ruby
-  concurrent-ruby-ext
-  d3-rails (~> 4.0)
+  d3-rails
  database_cleaner
  docker-api
  eventmachine (= 1.0.9.1)
@ -411,24 +420,24 @@ DEPENDENCIES
  forgery
  headless
  highline
-  ims-lti (= 1.1.10)
+  ims-lti (< 2.0.0)
  jbuilder
  jquery-rails
-  jquery-turbolinks
  kramdown
-  mnemosyne-ruby (~> 1.0)
+  listen
+  mnemosyne-ruby
  newrelic_rpm
  nokogiri
  nyan-cat-formatter
-  pagedown-rails
-  pg (< 1.0)
+  pagedown-bootstrap-rails
+  pg
  pry-byebug
  puma
  pundit
  rack-mini-profiler
-  rails (= 4.2.10)
+  rails (= 5.2.1)
+  rails-controller-testing
  rails-i18n
-  rake
  ransack
  rest-client
  rspec-autotest
@ -437,19 +446,18 @@ DEPENDENCIES
  rubocop-rspec
  rubytree
  rubyzip
-  sass-rails (>= 5.0.7)
-  sdoc
+  sass-rails
+  selenium-webdriver
  simplecov
  slim-rails
  sorcery
  spring
-  thread_safe
-  tubesock
-  turbolinks (< 5.0.0)
+  tubesock!
+  turbolinks
  uglifier
  web-console
+  webpacker
  whenever
-  will_paginate

 BUNDLED WITH
-   1.16.1
+   1.16.5
--- a/LOCAL_SETUP.md
+++ b/LOCAL_SETUP.md
@ -59,7 +59,7 @@ All problems that have occurred resulted from a more restrictive rights manageme
 ### Start server
 vagrant ssh  
 cd /vagrant  
-rails s -p 3000  
+rails s -p 3000 -b 0.0.0.0

 ### Login to CodeOcean
 192.168.59.104:3000  
--- a/README.md
+++ b/README.md
@ -4,7 +4,6 @@ Code Ocean
 [![Build Status](https://travis-ci.org/openHPI/codeocean.svg?branch=master)](https://travis-ci.org/openHPI/codeocean)
 [![Code Climate](https://codeclimate.com/github/openHPI/codeocean/badges/gpa.svg)](https://codeclimate.com/github/openHPI/codeocean)
 [![Test Coverage](https://codeclimate.com/github/openHPI/codeocean/badges/coverage.svg)](https://codeclimate.com/github/openHPI/codeocean)
-[![Dependency Status](https://gemnasium.com/openHPI/codeocean.svg)](https://gemnasium.com/openHPI/codeocean)

 ## Development Setup

--- a/1
+++ b/1
@ -7,6 +7,7 @@ Vagrant.configure(2) do |config|
    v.memory = 8192
  end
  config.vm.network "private_network", ip: "192.168.59.104"
+  config.vm.network "forwarded_port", guest: 3035, host: 3035
  # config.vm.synced_folder "../data", "/vagrant_data"
  config.vm.provision "shell", path: "provision.sh", privileged: false
 end
--- a/app/assets/images/.keep
+++ b/app/assets/images/.keep
--- a/app/assets/javascripts/application.js
+++ b/app/assets/javascripts/application.js
@ -10,20 +10,18 @@
 // Read Sprockets README (https://github.com/sstephenson/sprockets#sprockets-directives) for details
 // about supported directives.
 //
-//= require jquery
-//
-//= require ace/ace
-//= require chosen.jquery.min
-//= require jquery-ui.min
-//= require d3
-//= require jquery.turbolinks
 //= require jquery_ujs
-//= require jstree/jstree.min
 //= require turbolinks
-//= require_tree ../../../lib
+//= require pagedown_bootstrap
+//= require d3
+//
+// lib/assets
+//= require flash
+//= require url
+//
+// vendor/assets
+//= require ace/ace
+//= require ace/ext-language_tools
+//
+// app/assets
 //= require_tree .
-//= require bootstrap_pagedown
-//= require markdown.converter
-//= require markdown.sanitizer
-//= require markdown.editor
-//= require ace/ext-language_tools
--- a/app/assets/javascripts/base.js
+++ b/app/assets/javascripts/base.js
@ -8,20 +8,18 @@ window.CodeOcean = {
  }
 };

-$(function() {
-  var ANIMATION_DURATION = 500;
+var ANIMATION_DURATION = 500;

-  $.isController = function(name) {
-    return $('.container[data-controller="' + name + '"]').isPresent();
-  };
+$.isController = function(name) {
+  return $('.container[data-controller="' + name + '"]').isPresent();
+};

-  $.fn.isPresent = function() {
-    return this.length > 0;
-  };
+$.fn.isPresent = function() {
+  return this.length > 0;
+};

-  $.fn.scrollTo = function(selector) {
-    $(this).animate({
-      scrollTop: $(selector).offset().top - $(this).offset().top + $(this).scrollTop()
-    }, ANIMATION_DURATION);
-  };
-});
+$.fn.scrollTo = function(selector) {
+  $(this).animate({
+    scrollTop: $(selector).offset().top - $(this).offset().top + $(this).scrollTop()
+  }, ANIMATION_DURATION);
+};
--- a/app/assets/javascripts/bootstrap-dropdown-submenu.js
+++ b/app/assets/javascripts/bootstrap-dropdown-submenu.js
@ -1,4 +1,4 @@
-$(document).ready(function () {
+$(document).on('turbolinks:load', function() {

  var subMenusSelector = 'ul.dropdown-menu [data-toggle=dropdown]';

@ -14,7 +14,7 @@ $(document).ready(function () {
    var menu = $(this).parent().find("ul");
    var menupos = menu.offset();

-    var newPos;
+    var newPos = 0.0;
    if ((menupos.left + menu.width()) + 30 > $(window).width()) {
      newPos = -menu.width();
    } else {
--- a/app/assets/javascripts/dashboard.js
+++ b/app/assets/javascripts/dashboard.js
@ -1,4 +1,4 @@
-$(function() {
+$(document).on('turbolinks:load', function() {
  var CHART_START = window.vis ? vis.moment().add(-1, 'minute') : undefined;
  var DEFAULT_REFRESH_INTERVAL = 5000;

@ -51,6 +51,7 @@ $(function() {
    } else {
      var jqxhr = $.ajax({
        dataType: 'json',
+        url: '/admin/dashboard',
        method: 'GET'
      });
      jqxhr.done(function(response) {
--- a/app/assets/javascripts/editor.js.erb
+++ b/app/assets/javascripts/editor.js.erb
@ -1,4 +1,4 @@
-$(function() {
+$(document).on('turbolinks:load', function() {

  //Merge all editor components.
  $.extend(
--- a/app/assets/javascripts/editor/ajax.js.erb
+++ b/app/assets/javascripts/editor/ajax.js.erb
--- a/app/assets/javascripts/editor/editor.js.erb
+++ b/app/assets/javascripts/editor/editor.js.erb
@ -33,6 +33,7 @@ var CodeOceanEditor = {
  <% @config ||= CodeOcean::Config.new(:code_ocean).read(erb: false) %>
  sendEvents: <%= @config['codeocean_events'] ? @config['codeocean_events']['enabled'] : false %>,
  eventURL: "<%= @config['codeocean_events'] ? events_path : '' %>",
+  fileTypeURL: "<%= file_types_path %>",


 configureEditors: function () {
@ -43,7 +44,7 @@ configureEditors: function () {

  confirmDestroy: function (event) {
    event.preventDefault();
-    if (confirm($(this).data('message-confirm'))) {
+    if (confirm($(event.target).data('message-confirm'))) {
      this.destroyFile();
    }
  },
@ -63,7 +64,7 @@ configureEditors: function () {
    if ($('#output-' + index).isPresent()) {
      return $('#output-' + index);
    } else {
-      var element = $('<pre>').attr('id', 'output-' + index);
+      var element = $('<pre class="mt-2">').attr('id', 'output-' + index);
      $('#output').append(element);
      return element;
    }
@ -79,13 +80,13 @@ configureEditors: function () {
    }
  },

-  getPanelClass: function (result) {
+  getCardClass: function (result) {
    if (result.stderr && !result.score) {
-      return 'panel-danger';
+      return 'card bg-danger text-white';
    } else if (result.score < 1) {
-      return 'panel-warning';
+      return 'card bg-warning text-white';
    } else {
-      return 'panel-success';
+      return 'card bg-success text-white';
    }
  },

@ -107,11 +108,22 @@ configureEditors: function () {
    progress_bar.css('width', percentage + '%');
  },

+  // The event ready.jstree is fired too early and thus doesn't work.
+  selectFileInJsTree: function(filetree, file_id) {
+    if (!filetree.hasClass('jstree-loading')) {
+      filetree.jstree("deselect_all");
+      filetree.jstree().select_node(file_id);
+    } else {
+      setTimeout(this.selectFileInJsTree.bind(null, filetree, file_id), 250);
+    }
+  },
+
  showFirstFile: function() {
    var frame = $('.frame[data-role="main_file"]').isPresent() ? $('.frame[data-role="main_file"]') : $('.frame').first();
    var file_id = frame.find('.editor').data('file-id');
    this.setActiveFile(frame.data('filename'), file_id);
-    $('#files').jstree().select_node(file_id);
+    var filetree = $('#files');
+    this.selectFileInJsTree(filetree, file_id);
    this.showFrame(frame);
    this.toggleButtonStates();
  },
@ -124,11 +136,11 @@ configureEditors: function () {

  getProgressBarClass: function (percentage) {
    if (percentage < this.ADEQUATE_PERCENTAGE) {
-      return 'progress-bar progress-bar-striped progress-bar-danger';
+      return 'progress-bar progress-bar-striped bg-danger';
    } else if (percentage < this.SUCCESSFULL_PERCENTAGE) {
-      return 'progress-bar progress-bar-striped progress-bar-warning';
+      return 'progress-bar progress-bar-striped bg-warning';
    } else {
-      return 'progress-bar progress-bar-striped progress-bar-success';
+      return 'progress-bar progress-bar-striped bg-success';
    }
  },

@ -158,7 +170,7 @@ configureEditors: function () {
        category: 'editor_paste',
        data: pasteObject.text,
        exercise_id: $('#editor').data('exercise-id'),
-        file_id: $(this).data('file-id')
+        file_id: $(event.target).data('file-id')
      });
    }
  },
@ -177,8 +189,8 @@ configureEditors: function () {
  },

  resizeParentOfAceEditor: function (element){
-    // calculate needed size: window height - position of top of button-bar - 60 for bar itself and margins
-    var windowHeight = window.innerHeight - $('#editor-buttons').offset().top - 60;
+    // calculate needed size: window height - position of top of ACE editor - height of autosave label below editor - 5 for bar margins
+    var windowHeight = window.innerHeight - $(element).offset().top - $('#autosave-label').height() - 5;
    $(element).parent().height(windowHeight);
  },

@ -266,14 +278,29 @@ configureEditors: function () {
    this.initializeRequestForComments()
  },

+  updateEditorModeToFileTypeID: function (editor, fileTypeID) {
+    var newMode = 'ace/mode/text'
+
+    $.ajax(this.fileTypeURL + '/' + fileTypeID, {
+      dataType: 'json'
+    }).done(function (data) {
+        if (data['editor_mode'] !== null) {
+          newMode = data['editor_mode'];
+        }
+    }).fail(_.noop)
+      .always(function () {
+        ace.edit(editor).session.setMode(newMode);
+    });
+  },
+
  initializeFileTree: function () {
    $('#files').jstree($('#files').data('entries'));
    $('#files').on('click', 'li.jstree-leaf', function (event) {
-      active_file = {
-        filename: $(event.target).parent().text(),
-        id: parseInt($(event.target).parent().attr('id'))
-      };
-      var frame = $('[data-file-id="' + active_file.id + '"]').parent();
+      this.setActiveFile(
+        $(event.target).parent().text(),
+        parseInt($(event.target).parent().attr('id'))
+      );
+      var frame = $('[data-file-id="' + this.active_file.id + '"]').parent();
      this.showFrame(frame);
      this.toggleButtonStates();
    }.bind(this));
@ -296,8 +323,8 @@ configureEditors: function () {

  handleSideBarToggle: function() {
    $('#sidebar').toggleClass('sidebar-col').toggleClass('sidebar-col-collapsed');
-    $('#sidebar-collapsed').toggleClass('hidden');
-    $('#sidebar-uncollapsed').toggleClass('hidden');
+    $('#sidebar-collapsed').toggleClass('d-none');
+    $('#sidebar-uncollapsed').toggleClass('d-none');
  },

  initializeRegexes: function () {
@ -369,17 +396,17 @@ configureEditors: function () {
    return Modernizr.websockets;
  },

-  populatePanel: function (panel, result, index) {
-    panel.removeClass('panel-default').addClass(this.getPanelClass(result));
-    panel.find('.panel-title .filename').text(result.filename);
-    panel.find('.panel-title .number').text(index + 1);
-    panel.find('.row .col-sm-9').eq(0).find('.number').eq(0).text(result.passed);
-    panel.find('.row .col-sm-9').eq(0).find('.number').eq(1).text(result.count);
-    panel.find('.row .col-sm-9').eq(1).find('.number').eq(0).text(parseFloat((result.score * result.weight).toFixed(2)));
-    panel.find('.row .col-sm-9').eq(1).find('.number').eq(1).text(result.weight);
-    panel.find('.row .col-sm-9').eq(2).html(result.message);
-    if (result.error_messages) panel.find('.row .col-sm-9').eq(3).text(result.error_messages.join(' '));
-    //panel.find('.row .col-sm-9').eq(4).find('a').attr('href', '#output-' + index);
+  populateCard: function (card, result, index) {
+    card.addClass(this.getCardClass(result));
+    card.find('.card-title .filename').text(result.filename);
+    card.find('.card-title .number').text(index + 1);
+    card.find('.row .col-sm-9').eq(0).find('.number').eq(0).text(result.passed);
+    card.find('.row .col-sm-9').eq(0).find('.number').eq(1).text(result.count);
+    card.find('.row .col-sm-9').eq(1).find('.number').eq(0).text(parseFloat((result.score * result.weight).toFixed(2)));
+    card.find('.row .col-sm-9').eq(1).find('.number').eq(1).text(result.weight);
+    card.find('.row .col-sm-9').eq(2).html(result.message);
+    if (result.error_messages) card.find('.row .col-sm-9').eq(3).text(result.error_messages.join(' '));
+    //card.find('.row .col-sm-9').eq(4).find('a').attr('href', '#output-' + index);
  },

  publishCodeOceanEvent: function (payload) {
@ -409,7 +436,7 @@ configureEditors: function () {
      url: $('#editor').data('errors-url')
    });
    jqxhr.always(this.hideSpinner);
-    jqxhr.success(this.renderHint);
+    jqxhr.done(this.renderHint);
  },

  toggleButtonStates: function () {
@ -556,14 +583,14 @@ configureEditors: function () {
  },

  showOutputBar: function() {
-    $('#output_sidebar_collapsed').addClass('hidden');
-    $('#output_sidebar_uncollapsed').removeClass('hidden');
+    $('#output_sidebar_collapsed').addClass('d-none');
+    $('#output_sidebar_uncollapsed').removeClass('d-none');
    $('#output_sidebar').removeClass('output-col-collapsed').addClass('output-col');
  },

  hideOutputBar: function() {
-    $('#output_sidebar_collapsed').removeClass('hidden');
-    $('#output_sidebar_uncollapsed').addClass('hidden');
+    $('#output_sidebar_collapsed').removeClass('d-none');
+    $('#output_sidebar_uncollapsed').addClass('d-none');
    $('#output_sidebar').removeClass('output-col').addClass('output-col-collapsed');
  },

@ -572,16 +599,17 @@ configureEditors: function () {
  },

  initializeDescriptionToggle: function() {
-    $('#exercise-headline').on('click', this.toggleDescriptionPanel.bind(this));
-    $('a#toggle').on('click', this.toggleDescriptionPanel.bind(this));
+    $('#exercise-headline').on('click', this.toggleDescriptionCard.bind(this));
+    $('a#toggle').on('click', this.toggleDescriptionCard.bind(this));
  },

-  toggleDescriptionPanel: function() {
-    $('#description-panel').toggleClass('description-panel-collapsed').toggleClass('description-panel');
+  toggleDescriptionCard: function() {
+    $('#description-card').toggleClass('description-card-collapsed').toggleClass('description-card');
    $('#description-symbol').toggleClass('fa-chevron-down').toggleClass('fa-chevron-right');
    var toggle = $('a#toggle');
    toggle.text(toggle.text() == toggle.data('hide') ? toggle.data('show') : toggle.data('hide'));
    this.resizeAceEditors();
+    event.preventDefault();
  },

    /**
--- a/app/assets/javascripts/editor/evaluation.js.erb
+++ b/app/assets/javascripts/editor/evaluation.js.erb
@ -9,7 +9,7 @@ CodeOceanEditorEvaluation = {
    this.clearScoringOutput();
    this.createSubmission('#assess', null, function (response) {
      this.showSpinner($('#assess'));
-      $('#score_div').removeClass('hidden');
+      $('#score_div').removeClass('d-none');
      var url = response.score_url;
      this.initializeSocketForScoring(url);
    }.bind(this));
@ -26,9 +26,9 @@ CodeOceanEditorEvaluation = {

  printScoringResult: function (result, index) {
    $('#results').show();
-    var panel = $('#dummies').children().first().clone();
-    this.populatePanel(panel, result, index);
-    $('#results ul').first().append(panel);
+    var card = $('#dummies').children().first().clone();
+    this.populateCard(card, result, index);
+    $('#results ul').first().append(card);
  },

  printScoringResults: function (response) {
@ -60,7 +60,7 @@ CodeOceanEditorEvaluation = {
  renderHint: function (object) {
    var hint = object.data || object.hint;
    if (hint) {
-      $('#hint .panel-body').text(hint);
+      $('#hint .card-body').text(hint);
      $('#hint').fadeIn();
    }
  },
@ -152,22 +152,22 @@ CodeOceanEditorEvaluation = {
    var element = this.findOrCreateOutputElement(index);
    if (!colorize) {
      if (output.stdout != undefined && output.stdout != '') {
-        element.append(output.stdout)
-        //element.text(element.text() + output.stdout)
+        //element.append(output.stdout)
+        element.text(element.text() + output.stdout)
      }

      if (output.stderr != undefined && output.stderr != '') {
-          element.append('StdErr: ' + output.stderr);
-        //element.text('StdErr: ' + element.text() + output.stderr);
+        //element.append('StdErr: ' + output.stderr);
+        element.text('StdErr: ' + element.text() + output.stderr);
      }

    } else if (output.stderr) {
-        element.addClass('text-warning').append(output.stderr);
-        //element.addClass('text-warning').text(element.text() + output.stderr);
+        //element.addClass('text-warning').append(output.stderr);
+        element.addClass('text-warning').text(element.text() + output.stderr);
      this.QaApiOutputBuffer.stderr += output.stderr;
    } else if (output.stdout) {
-        element.addClass('text-success').append(output.stdout);
-        //element.addClass('text-success').text(element.text() + output.stdout);
+        //element.addClass('text-success').append(output.stdout);
+        element.addClass('text-success').text(element.text() + output.stdout);
      this.QaApiOutputBuffer.stdout += output.stdout;
    } else {
      element.addClass('text-muted').text($('#output').data('message-no-output'));
--- a/app/assets/javascripts/editor/execution.js.erb
+++ b/app/assets/javascripts/editor/execution.js.erb
@ -2,8 +2,9 @@ CodeOceanEditorWebsocket = {
  websocket: null,

  createSocketUrl: function(url) {
-      var sockURL = new URL(window.location);
-      sockURL.pathname = url;
+      var sockURL = new URL(url, window.location);
+      // not needed any longer, we put it directly into the url: sockURL.pathname = url;
+
      // sanitize socket protocol string, strip trailing slash and other malicious chars if they are there
      sockURL.protocol = '<%= DockerClient.config['ws_client_protocol']&.match(/(\w+):*\/*/)&.to_a&.at(1) %>:';

--- a/app/assets/javascripts/editor/participantsupport.js.erb
+++ b/app/assets/javascripts/editor/participantsupport.js.erb
@ -90,7 +90,6 @@ CodeOceanEditorFlowr = {
        var collapsibleTileHtml = self.flowrResultHtml
          .replace(/{{collapseId}}/g, 'collapse-' + index).replace(/{{headingId}}/g, 'heading-' + index);
        var resultTile = $(collapsibleTileHtml);
-
        var questionUrl = 'https://stackoverflow.com/questions/' + result.question_id;

        var header = resultTile.find('h4 > a');
@ -162,7 +161,7 @@ CodeOceanEditorRequestForComments = {
        $.flash.success({text: $('#askForCommentsButton').data('message-success')});
        // trigger a run
        this.runSubmission.call(this, submission);
-      }.bind(this)).error(this.ajaxError.bind(this));
+      }.bind(this)).fail(this.ajaxError.bind(this));
    };

    this.createSubmission($('#requestComments'), null, createRequestForComments.bind(this));
--- a/app/assets/javascripts/editor/prompt.js.erb
+++ b/app/assets/javascripts/editor/prompt.js.erb
@ -2,19 +2,19 @@ CodeOceanEditorPrompt = {
    prompt: '#prompt',

    showPrompt: function(msg) {
-        var label = $('#prompt .input-group-addon');
+        var label = $('#prompt .input-group-text');
        var prompt = $(this.prompt);
        label.text(msg.data || label.data('prompt'));
-        if (prompt.isPresent() && prompt.hasClass('hidden')) {
-            prompt.removeClass('hidden');
+        if (prompt.isPresent() && prompt.hasClass('d-none')) {
+            prompt.removeClass('d-none');
        }
        $('#prompt input').focus();
    },

    hidePrompt: function() {
        var prompt = $(this.prompt);
-        if (prompt.isPresent() && !prompt.hasClass('hidden')) {
-            prompt.addClass('hidden');
+        if (prompt.isPresent() && !prompt.hasClass('d-none')) {
+            prompt.addClass('d-none');
        }
    },

--- a/app/assets/javascripts/editor/submissions.js.erb
+++ b/app/assets/javascripts/editor/submissions.js.erb
@ -106,14 +106,16 @@ CodeOceanEditorSubmissions = {
    this.ajax({
      method: 'GET',
      url: $('#start-over').data('url')
-    }).success(function(response) {
+    }).done(function(response) {
      this.hideSpinner();
      _.each(this.editors, function(editor) {
        var file_id = $(editor.container).data('file-id');
        var file = _.find(response.files, function(file) {
          return file.id === file_id;
        });
-        editor.setValue(file.content);
+        if(file){
+            editor.setValue(file.content);
+        }
      }.bind(this));
    }.bind(this));
  },
@ -153,7 +155,7 @@ CodeOceanEditorSubmissions = {
    $('#stop').data('url', submission.stop_url);
    this.running = true;
    this.showSpinner($('#run'));
-    $('#score_div').addClass('hidden');
+    $('#score_div').addClass('d-none');
    this.toggleButtonStates();
    var url = submission.run_url.replace(this.FILENAME_URL_PLACEHOLDER, this.active_file.filename.replace(/#$/,'')); // remove # if it is the last character, this is not part of the filename and just an anchor
    this.initializeSocketForRunning(url);
@ -173,8 +175,8 @@ CodeOceanEditorSubmissions = {
    if ($('#test').is(':visible')) {
      this.createSubmission('#test', null, function(response) {
        this.showSpinner($('#test'));
-        $('#score_div').addClass('hidden');
-        var url = response.test_url.replace(this.FILENAME_URL_PLACEHOLDER, this.active_file.filenamereplace(/#$/,'')); // remove # if it is the last character, this is not part of the filename and just an anchor
+        $('#score_div').addClass('d-none');
+        var url = response.test_url.replace(this.FILENAME_URL_PLACEHOLDER, this.active_file.filename.replace(/#$/,'')); // remove # if it is the last character, this is not part of the filename and just an anchor
        this.initializeSocketForTesting(url);
      }.bind(this));
    }
--- a/app/assets/javascripts/editor/turtle.js.erb
+++ b/app/assets/javascripts/editor/turtle.js.erb
@ -38,10 +38,10 @@ CodeOceanEditorTurtle = {

  showCanvas: function () {
    if ($('#turtlediv').isPresent()
-        && this.turtlecanvas.hasClass('hidden')) {
+        && this.turtlecanvas.hasClass('d-none')) {
      // initialize two-column layout
      $('#output-col1').addClass('col-lg-7 col-md-7 two-column');
-      this.turtlecanvas.removeClass('hidden');
+      this.turtlecanvas.removeClass('d-none');
    }
  }

--- a/app/assets/javascripts/editor/websocket.js.erb
+++ b/app/assets/javascripts/editor/websocket.js.erb
--- a/app/assets/javascripts/editor_edit.js.erb
+++ b/app/assets/javascripts/editor_edit.js.erb
--- a/app/assets/javascripts/error_templates.js
+++ b/app/assets/javascripts/error_templates.js
@ -1,4 +1,4 @@
-$(function() {
+$(document).on('turbolinks:load', function() {
    if ($.isController('error_templates')) {
        $('#add-attribute').find('button').on('click', function () {
            $.ajax(location + '/attribute.json', {
@ -8,9 +8,9 @@ $(function() {
                    dataType: 'json',
                    error_template_attribute_id: $('#add-attribute').find('select').val()
                }
-            }).success(function () {
+            }).done(function () {
                location.reload();
-            }).error(function (error) {
+            }).fail(function (error) {
                $.flash.danger({text: error.statusText});
            });
        });
--- a/app/assets/javascripts/execution_environments.js
+++ b/app/assets/javascripts/execution_environments.js
@ -1,4 +1,4 @@
-$(function() {
+$(document).on('turbolinks:load', function() {
  if ($.isController('execution_environments')) {
    if ($('.edit_execution_environment, .new_execution_environment').isPresent()) {
      new MarkdownEditor('#execution_environment_help');
--- a/app/assets/javascripts/exercise_collections.js.erb
+++ b/app/assets/javascripts/exercise_collections.js.erb
@ -1,4 +1,4 @@
-$(function() {
+$(document).on('turbolinks:load', function() {
  if ($.isController('exercise_collections')) {
    var dataElement = $('#data');
    var exerciseList = $('#exercise-list');
--- a/app/assets/javascripts/exercise_graphs.js
+++ b/app/assets/javascripts/exercise_graphs.js
@ -1,4 +1,4 @@
-$(function() {
+$(document).on('turbolinks:load', function() {
    // /exercises/38/statistics good for testing

    if ($.isController('exercises') && $('.graph-functions-2').isPresent()) {
--- a/app/assets/javascripts/exercises.js.erb
+++ b/app/assets/javascripts/exercises.js.erb
@ -1,4 +1,4 @@
-$(function() {
+$(document).on('turbolinks:load', function() {
  // ruby part adds the relative_url_root, if it is set.
  var ACE_FILES_PATH = '<%= (defined?  Rails.application.config.relative_url_root) &&  Rails.application.config.relative_url_root != nil &&  Rails.application.config.relative_url_root != "" ?  Rails.application.config.relative_url_root : "" %>' + '/assets/ace/';
  var THEME = 'ace/theme/textmate';
@ -66,10 +66,9 @@ $(function() {
    $('#files').append(html);
    $('#files li:last select[name*="file_type_id"]').val(getSelectedExecutionEnvironment().file_type_id);
    $('#files li:last select').chosen(window.CodeOcean.CHOSEN_OPTIONS);
+    $('#files li:last select').remove();
+    $('#files li:last>div:last').removeClass('in').addClass('show')
    $('body, html').scrollTo('#add-file');
-    // if we collapse the file forms by default, we need to click on the new element in order to open it.
-    // however, this crashes for more files (if we add several ones by clicking the add button more often), since the elements are probably not correctly added to the files list.
-    //$('#files li:last>div:first>a>div').click();

    // initialize the ace editor for the new textarea.
    // pass the correct index and the last ace editor under the node files. this is the last one, since we just added it.
@ -93,7 +92,7 @@ $(function() {

  var deleteFile = function(event) {
    event.preventDefault();
-    var fileUrl = $(this).data('file-url');
+    var fileUrl = $(event.target).data('file-url');

    if (confirm('<%= I18n.t('shared.confirm_destroy') %>')) {
      var jqxhr = $.ajax({
@ -139,9 +138,9 @@ $(function() {
  var enableBatchUpdate = function() {
    $('thead .batch a').on('click', function(event) {
      event.preventDefault();
-      if (!$(this).data('toggled')) {
-        $(this).data('toggled', true);
-        $(this).text($(this).data('text'));
+      if (!$(event.target).data('toggled')) {
+        $(event.target).data('toggled', true);
+        $(event.target).text($(event.target).data('text'));
        buildCheckboxes();
      } else {
        performBatchUpdate();
@ -199,7 +198,7 @@ $(function() {
  var observeFileRoleChanges = function() {
    $(document).on('change', 'select[name$="[role]"]', function() {
      var is_test_file = $(this).val() === 'teacher_defined_test';
-      var parent = $(this).parents('.panel');
+      var parent = $(this).parents('.card');
      var fields = parent.find('.test-related-fields');
      if (is_test_file) {
        fields.slideDown();
@ -262,17 +261,13 @@ $(function() {
      jqxhr.fail(ajaxError);
  }

-  if ($.isController('exercises')) {
+  if ($.isController('exercises') || $.isController('submissions')) {
      // ignore tags table since it is in the dom before other tables
    if ($('table:not(#tags-table)').isPresent()) {
      enableBatchUpdate();
    } else if ($('.edit_exercise, .new_exercise').isPresent()) {
      execution_environments = $('form').data('execution-environments');
      file_types = $('form').data('file-types');
-      // new MarkdownEditor('#exercise_instructions');
-      // new MarkdownEditor('#exercise_description')
-      // todo: add an ace editor for each file
-      new PagedownEditor('#exercise_description');

      enableInlineFileCreation();
      inferFileAttributes();
--- a/app/assets/javascripts/external_users.js
+++ b/app/assets/javascripts/external_users.js
@ -1,4 +1,4 @@
-$(function() {
+$(document).on('turbolinks:load', function() {
  var grid = $('#tag-grid');

  if ($.isController('external_users') && grid.isPresent()) {
--- a/app/assets/javascripts/forms.js
+++ b/app/assets/javascripts/forms.js
@ -1,4 +1,4 @@
-$(function() {
+$(document).on('turbolinks:load', function() {
  var CHOSEN_OPTIONS = {
    allow_single_deselect: true,
    disable_search_threshold: 5,
@ -14,11 +14,11 @@ $(function() {
      var alternative_input = parent.find('.alternative-input');

      if (alternative_input.attr('disabled')) {
-        $(this).text($(this).data('text-toggled'));
+        $(this).text($(event.target).data('text-toggled'));
        original_input.attr('disabled', true).hide();
        alternative_input.attr('disabled', false).show();
      } else {
-        $(this).text($(this).data('text-initial'));
+        $(this).text($(event.target).data('text-initial'));
        alternative_input.attr('disabled', true).hide();
        original_input.attr('disabled', false).show();
      }
@ -26,5 +26,27 @@ $(function() {
  });

  window.CodeOcean.CHOSEN_OPTIONS = CHOSEN_OPTIONS;
-  $('select:visible').chosen(CHOSEN_OPTIONS);
+  chosen_inputs = $('select').filter(function(){
+    return !$(this).parents('ul').is('#dummies');
+  });
+
+  // enable chosen hook when editing an exercise to update ace code highlighting
+  if ($.isController('exercises') && $('.edit_exercise, .new_exercise').isPresent()) {
+      chosen_inputs.filter(function(){
+          return $(this).attr('id').includes('file_type_id');
+      }).on('change chosen:ready', function(event, parameter) {
+          // Set ACE editor mode (for code highlighting) on change of file type and after initialization
+          editorInstance = $(event.target).closest('.card-body').find('.editor')[0];
+          selectedFileType = event.target.value;
+          CodeOceanEditor.updateEditorModeToFileTypeID(editorInstance, selectedFileType);
+      })
+  }
+
+  chosen_inputs.chosen(CHOSEN_OPTIONS);
+});
+
+// Remove some elements before going back to an older site. Otherwise, they might not work.
+$(document).on('turbolinks:before-cache', function() {
+    $('.chosen-container').remove();
+    $('#wmd-button-row-description').remove();
 });
--- a/app/assets/javascripts/markdown_ace_editor.js
+++ b/app/assets/javascripts/markdown_ace_editor.js
@ -9,7 +9,7 @@
        });
        editor.setShowPrintMargin(false);
        var session = editor.getSession();
-        session.setMode('markdown');
+        session.setMode('ace/mode/markdown');
        session.setUseWrapMode(true);
        session.setValue($(selector).val());
    };
--- a/app/assets/javascripts/pagedown.js
+++ b/app/assets/javascripts/pagedown.js
@ -1,10 +0,0 @@
-(function() {
-    var ACE_FILES_PATH = '/assets/ace/';
-
-    window.PagedownEditor = function(selector) {
-        var converter = Markdown.getSanitizingConverter();
-        var editor    = new Markdown.Editor( converter );
-
-        editor.run();
-    };
-})();
--- a/app/assets/javascripts/pagedown/markdown.editor.js.erb
+++ b/app/assets/javascripts/pagedown/markdown.editor.js.erb
--- a/app/assets/javascripts/pagedown/pagedown.js.erb
+++ b/app/assets/javascripts/pagedown/pagedown.js.erb
@ -0,0 +1,43 @@
+//= require markdown.converter
+//  markdown.editor is slightly adjusted to work with Bootstrap 4.
+//  Taken from https://github.com/hughevans/pagedown-bootstrap-rails, V2.1.4
+//= require markdown.editor
+//= require markdown.sanitizer
+//= require markdown.extra
+
+renderPagedown = function() {
+    $(".wmd-output").each(function (i) {
+        const converter = new Markdown.Converter();
+        const content = $(this).html();
+        return $(this).html(converter.makeHtml(content));
+    })
+};
+
+createPagedownEditor = function( selector, context ) {
+    if (context == null) { context = 'body'; }
+    return $(selector, context).each(function(i, input) {
+        if ($(input).data('is_rendered')) {
+            return;
+        }
+        const attr = $(input).attr('id').split('wmd-input')[1];
+        const converter = new Markdown.Converter();
+        Markdown.Extra.init(converter);
+        const help = {
+            handler() {
+                window.open('http://daringfireball.net/projects/markdown/syntax');
+                return false;
+            },
+            title: "<%= I18n.t('components.markdown_editor.help', default: 'Markdown Editing Help') %>"
+        };
+
+        const editor = new Markdown.Editor(converter, attr, help);
+        editor.run();
+        $('[data-toggle="tooltip"]').tooltip();
+        return $(input).data('is_rendered', true);
+    });
+};
+
+$(document).on('turbolinks:load', function() {
+    renderPagedown();
+    return createPagedownEditor('.wmd-input');
+});
--- a/app/assets/javascripts/shell.js
+++ b/app/assets/javascripts/shell.js
@ -1,4 +1,4 @@
-$(function() {
+$(document).on('turbolinks:load', function() {
  var ENTER_KEY_CODE = 13;

  var clearOutput = function() {
--- a/app/assets/javascripts/sortable.js
+++ b/app/assets/javascripts/sortable.js
@ -1,4 +1,4 @@
-$(document).ready(function(){
+$(document).on('turbolinks:load', function(){
  (function vendorTableSorter(){
    /*
      SortTable
--- a/app/assets/javascripts/statistics_activity_history.js
+++ b/app/assets/javascripts/statistics_activity_history.js
@ -1,4 +1,4 @@
-$(document).ready(function () {
+$(document).on('turbolinks:load', function() {

  function manageActivityHistory(prefix) {
    var containerId = prefix + '-activity-history';
@ -49,7 +49,7 @@ $(document).ready(function () {

      var refreshData = function (callback) {
        var params = new URLSearchParams(window.location.search.slice(1));
-        var jqxhr = $.ajax(prefix + '-activity-history.json', {
+        var jqxhr = $.ajax('/statistics/graphs/' + prefix + '-activity-history.json', {
          dataType: 'json',
          data: {from: params.get('from'), to: params.get('to'), interval: params.get('interval')},
          method: 'GET'
--- a/app/assets/javascripts/statistics_graphs.js
+++ b/app/assets/javascripts/statistics_graphs.js
@ -1,4 +1,4 @@
-$(document).ready(function () {
+$(document).on('turbolinks:load', function() {
  if ($.isController('statistics') && $('.graph#user-activity').isPresent()) {

    function manageGraph(containerId, url, refreshAfter) {
@ -101,7 +101,7 @@ $(document).ready(function () {
      });
    }

-    manageGraph('user-activity', 'graphs/user-activity', 10);
-    manageGraph('rfc-activity', 'graphs/rfc-activity', 30);
+    manageGraph('user-activity', '/statistics/graphs/user-activity', 10);
+    manageGraph('rfc-activity', '/statistics/graphs/rfc-activity', 30);
  }
 });
--- a/app/assets/javascripts/submission_statistics.js
+++ b/app/assets/javascripts/submission_statistics.js
@ -1,34 +1,44 @@
-$(function() {
+$(document).on('turbolinks:load', function() {

  var ACE_FILES_PATH = '/assets/ace/';
  var THEME = 'ace/theme/textmate';

  var currentSubmission = 0;
  var active_file = undefined;
-  var fileTrees = []
+  var fileTrees = [];
  var editor = undefined;
-  var fileTypeById = {}
+  var fileTypeById = {};

  var showActiveFile = function() {
    var session = editor.getSession();
-    var fileType = fileTypeById[active_file.file_type_id]
+    var fileType = fileTypeById[active_file.file_type_id];
    session.setMode(fileType.editor_mode);
    session.setTabSize(fileType.indent_size);
    session.setValue(active_file.content);
    session.setUseSoftTabs(true);
    session.setUseWrapMode(true);

+    // The event ready.jstree is fired too early and thus doesn't work.
+    var selectFileInJsTree = function() {
+      if (!filetree.hasClass('jstree-loading')) {
+        filetree.jstree("deselect_all");
+        filetree.jstree().select_node(active_file.file_id);
+      } else {
+        setTimeout(selectFileInJsTree, 250);
+      }
+    };
+
+    filetree = $(fileTrees[currentSubmission]);
+    selectFileInJsTree();
+    // Finally change jstree element to prevent flickering
    showFileTree(currentSubmission);
-    filetree = $(fileTrees[currentSubmission])
-    filetree.jstree("deselect_all");
-    filetree.jstree().select_node(active_file.file_id);
  };

  var initializeFileTree = function() {
    $('.files').each(function(index, element) {
      fileTree = $(element).jstree($(element).data('entries'));
      fileTree.on('click', 'li.jstree-leaf', function() {
-        var id = parseInt($(this).attr('id'))
+        var id = parseInt($(this).attr('id'));
        _.each(files[currentSubmission], function(file) {
          if (file.file_id === id) {
            active_file = file;
@ -42,8 +52,8 @@ $(function() {

  var showFileTree = function(index) {
    $('.files').hide();
-    $(fileTrees[index].context).show();
-  }
+    $(fileTrees[index]).show();
+  };

  if ($.isController('exercises') && $('#timeline').isPresent()) {

@ -85,7 +95,7 @@ $(function() {
        if (file.name === active_file.name) {
          fileIndex = index;
        }
-      })
+      });
      active_file = currentFiles[fileIndex];
      showActiveFile();
    });
@ -94,10 +104,10 @@ $(function() {
      clearInterval(playInterval);
      playInterval = undefined;
      playButton.find('span.fa').removeClass('fa-pause').addClass('fa-play')
-    }
+    };

    playButton.on('click', function(event) {
-      if (playInterval == undefined) {
+      if (playInterval === undefined) {
        playInterval = setInterval(function() {
          if ($.isController('exercises') && $('#timeline').isPresent() && slider.val() < submissions.length - 1) {
            slider.val(parseInt(slider.val()) + 1);
@ -112,7 +122,7 @@ $(function() {
      }
    });

-    active_file = files[0][0]
+    active_file = files[0][0];
    initializeFileTree();
    showActiveFile();
  }
--- a/app/assets/javascripts/working_time_graphs.js
+++ b/app/assets/javascripts/working_time_graphs.js
@ -1,4 +1,4 @@
-$(function() {
+$(document).on('turbolinks:load', function() {
    // http://localhost:3333/exercises/38/statistics good for testing
    // originally at--> localhost:3333/exercises/69/statistics

@ -30,7 +30,7 @@ $(function() {
          var studentTime = minutes_array[i];

          for (var j = 0; j < studentTime; j++){
-              if (minutes_count[j] == undefined){
+              if (minutes_count[j] === undefined){
                  minutes_count[j] = 0;
              } else{
                  minutes_count[j] += 1;
@ -173,23 +173,23 @@ $(function() {
      //}

      // DRAW THE SECOND GRAPH ------------------------------------------------------------------------------
-      //<script src="http://labratrevenge.com/d3-tip/javascripts/d3.tip.v0.6.3.js"></script>
      function draw_bar_graph() {
-          var group_incrament = 5;
-          var group_ranges = group_incrament; // just for the start
+          var number_of_bars = 40;
+          var group_increment = Math.ceil(maximum_minutes / number_of_bars); // range in minutes
+          var group_ranges = group_increment; // just for the start
          var minutes_array_for_bar = [];

          do {
              var section_value = 0;
              for (var i = 0; i < minutes_array.length; i++) {
-                  if ((minutes_array[i] < group_ranges) && (minutes_array[i] >= (group_ranges - group_incrament))) {
+                  if ((minutes_array[i] < group_ranges) && (minutes_array[i] >= (group_ranges - group_increment))) {
                      section_value++;
                  }
              }
              minutes_array_for_bar.push(section_value);
-              group_ranges += group_incrament;
+              group_ranges += group_increment;
          }
-          while (group_ranges < maximum_minutes + group_incrament);
+          while (group_ranges < maximum_minutes + group_increment);

          //console.log(minutes_array_for_bar); // this var used as the bars
          //minutes_array_for_bar = [39, 20, 28, 20, 39, 34, 26, 23, 16, 8];
@ -199,30 +199,30 @@ $(function() {


          var width_ratio = .8;
+          if (getWidth()*width_ratio > 1000){
+              width_ratio = 1000/getWidth();
+          }
          var height_ratio = .7; // percent of height

          var margin = {top: 100, right: 20, bottom: 70, left: 70},//30,50
              width = (getWidth() * width_ratio) - margin.left - margin.right,
              height = (width * height_ratio) - margin.top - margin.bottom;

-          var x = d3.scale.ordinal()
-              .rangeRoundBands([0, width], .1);
+          var x = d3.scaleBand()
+              .range([0, width], .1);

          var y = d3.scaleLinear()
              .range([0,height-(margin.top + margin.bottom)]);


-          var xAxis = d3.svg.axis()
-              .scale(x)
-              .orient("bottom")
+          var xAxis = d3.axisBottom(x)
              .ticks(10);


-          var yAxis = d3.svg.axis()
-              .scale(d3.scaleLinear().domain([0,max_of_array]).range([height,0]))//y
-              .orient("left")
+          var yAxis = d3
+              .axisLeft(d3.scaleLinear().domain([0,max_of_array]).range([height,0]))//y
              .ticks(10)
-              .innerTickSize(-width);
+              .tickSizeInner(-width);

          var tip = d3.tip()
              .attr('class', 'd3-tip')
@ -241,8 +241,8 @@ $(function() {

          x.domain(minutes_array_for_bar.map(function (d, i) {
              i++;
-              var high_side = i * group_incrament;
-              var low_side = high_side - group_incrament;
+              var high_side = i * group_increment;
+              var low_side = high_side - group_increment;
              return (low_side+"-"+high_side);
          }));

@ -253,7 +253,14 @@ $(function() {
          svg.append("g")
              .attr("class", "x axis")
              .attr("transform", "translate(0," + height + ")")
-              .call(xAxis);
+              .call(xAxis)
+              .selectAll("text")
+              .style("text-anchor", "end")
+              .attr("dx", "-.8em")
+              .attr("dy", ".15em")
+              .attr("transform", function(d) {
+                  return "rotate(-45)"
+              });

          svg.append("g")
              .attr("class", "y axis")
@ -278,7 +285,7 @@ $(function() {
              .attr("text-anchor", "middle")
              .attr("x", width / 2)
              .attr("y", height)
-              .attr("dy", ((height / 20) + 20) + 'px')
+              .attr("dy", ((height / 20) + 40) + 'px')
              .text("Working Time (Minutes)")
              .style('font-size', 14);

@ -291,10 +298,10 @@ $(function() {
              .data(minutes_array_for_bar)
              .enter().append("rect")
              .attr("class", "bar")
-              .attr("x", function(d,i) {    var bar_incriment = width/ minutes_array_for_bar.length;
-                                            var bar_x = i * bar_incriment;
+              .attr("x", function(d,i) {    var bar_increment = width / minutes_array_for_bar.length;
+                                            var bar_x = i * bar_increment;
                                            return (bar_x)})
-              .attr("width", x.rangeBand())
+              .attr("width", x.bandwidth())
              .attr("y", function(d) { return height - y(d); })
              .attr("height", function(d) { return y(d); })
              .on('mouseover', tip.show)
@ -311,7 +318,7 @@ $(function() {
              .style('text-decoration', 'underline');

      }
-      // draw_bar_graph();
+      draw_bar_graph();
  }

 });
--- a/app/assets/stylesheets/application.css
+++ b/app/assets/stylesheets/application.css
@ -10,10 +10,11 @@
 * defined in the other CSS/SCSS files in this directory. It is generally better to create a new
 * file per style scope.
 *
+ *= require pagedown_bootstrap
+ *
+ * lib/assets
+ *= require flash
+ *
+ * app/assets
 *= require_tree .
- *= require_tree ../../../lib
- *= require_tree ../../../vendor/assets/stylesheets/
- *= require_self
- *= require bootstrap_pagedown
- *= require markdown
 */
--- a/app/assets/stylesheets/base.css.scss
+++ b/app/assets/stylesheets/base.css.scss
@ -3,6 +3,10 @@ h1 {
  margin-bottom: 0.5em;
 }

+h1, h2, h3, h4, h5, h6 {
+  font-weight: 500;
+}
+
 .lead {
  font-size: 16px;
  color: rgba(70, 70, 70, 1);
@ -15,28 +19,47 @@ i.fa {
 pre {
  background-color: #FAFAFA;
  margin: 0;
-  padding: 0;
+  padding: .25rem!important;
+  border: 1px solid #CCCCCC;
 }

 span.caret {
  margin-left: 0.5em;
 }

+.btn {
+  -webkit-font-smoothing: antialiased;
+  font-weight: 500;
+  :not(.btn-lg) {
+    font-size: 0.875rem;
+  }
+}
+
 .progress {
  margin: 0;
+  border: 1px solid #CCCCCC;
+  padding: 0.125rem !important;
+  height: 1.25rem !important;

  .progress-bar {
    line-height: initial;
    min-width: 2em;
+    color: white;
  }
 }

+.navbar {
+  -webkit-font-smoothing: antialiased;
+  font-weight: 500;
+}
+
 .attribute-row + .attribute-row {
  margin-top: 0.5em;
 }

-.badge {
+.badge-pill {
  font-size: 100%;
+  font-weight: 500;
 }

 .container[data-controller] {
--- a/app/assets/stylesheets/bootstrap-dropdown-submenu.css.scss
+++ b/app/assets/stylesheets/bootstrap-dropdown-submenu.css.scss
@ -3,10 +3,14 @@
 }

 .dropdown-submenu > .dropdown-menu {
-  top: 0;
+  top: -0.2em;
  left: 100%;
 }

+.dropdown-submenu.open > ul.dropdown-menu  {
+  display: block;
+}
+
 .dropdown-submenu > a:after {
  display: block;
  content: " ";
@ -25,11 +29,11 @@
  border-left-color: #ffffff;
 }

-.dropdown-submenu.pull-left {
+.dropdown-submenu.float-left {
  float: none;
 }

-.dropdown-submenu.pull-left > .dropdown-menu {
+.dropdown-submenu.float-left > .dropdown-menu {
  left: -100%;
  margin-left: 10px;
  -webkit-border-radius: 6px 0 6px 6px;
--- a/app/assets/stylesheets/editor.css.scss
+++ b/app/assets/stylesheets/editor.css.scss
@ -45,10 +45,6 @@ button i.fa-spin {
  width: 100%;
  display: flex;

-  button {
-    font-size: 80%;
-  }
-
  button, .btn-group {
    flex-grow: 1;
  }
@ -144,7 +140,8 @@ button i.fa-spin {
  min-height: 1px;
  padding-left: 15px;
  padding-right: 15px;
-  box-sizing: border-box
+  box-sizing: border-box;
+  margin-left: auto;
 }

 .output-col-collapsed {
@ -155,7 +152,8 @@ button i.fa-spin {
  min-height: 1px;
  padding-left: 15px;
  padding-right: 15px;
-  box-sizing: border-box
+  box-sizing: border-box;
+  margin-left: auto;
 }

 .enforce-top-margin {
@ -166,14 +164,14 @@ button i.fa-spin {
  margin-right: 10px !important;
 }

-.description-panel-collapsed {
+.description-card-collapsed {
  -webkit-transition: width 2s;
  transition: width 2s;
  height: 0px;
  visibility: hidden;
 }

-.description-panel {
+.description-card {
  height: auto;
  -webkit-transition: height 2s;
  transition: height 2s;
--- a/app/assets/stylesheets/exercise_collections.scss
+++ b/app/assets/stylesheets/exercise_collections.scss
@ -57,10 +57,6 @@ rect.value-bar {
  }
 }

-.table-responsive#exercise-list {
-  max-height: 512px;
-}
-
 .exercise-id-tooltip {
  position: absolute;
  display: none;
--- a/app/assets/stylesheets/exercises.css.scss
+++ b/app/assets/stylesheets/exercises.css.scss
@ -35,11 +35,19 @@ input[type='file'] {
    margin: 10px 0 10px 0;
  }

-  .lead.description-panel-collapsed {
+  .lead.description-card-collapsed {
    margin: 0;
  }
 }

+[data-toggle="collapse"] .fa:before {
+  content: "\f139";
+}
+
+[data-toggle="collapse"].collapsed .fa:before {
+  content: "\f13a";
+}
+
 // Graph Settings

 .axis path {
--- a/app/assets/stylesheets/request-for-comments.css.scss
+++ b/app/assets/stylesheets/request-for-comments.css.scss
@ -68,8 +68,10 @@
    .result {
      margin-right: 10px;
      margin-top: 20px;
-      width: 10px;
-      height: 10px;
+      min-width: 10px;
+      max-width: 10px;
+      min-height: 10px;
+      max-height: 10px;
    }

    .passed {
@ -127,7 +129,7 @@
  background-color:#f9f9f9
 }

-.ace_tooltip {
+:not(.allow_ace_tooltip) > .ace_tooltip {
  display: none !important;
 }

--- a/app/assets/stylesheets/statistics.css.scss
+++ b/app/assets/stylesheets/statistics.css.scss
@ -76,8 +76,8 @@ tr.highlight {
  grid-gap: 10px;

  > a {
-    color: #fff;
-    text-decoration: none;
+    color: #fff !important;
+    text-decoration: none !important;

    > div {
      border: 2px solid #0055ba;
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@ -6,7 +6,7 @@ class ApplicationController < ActionController::Base

  after_action :verify_authorized, except: [:help, :welcome]
  before_action :set_locale, :allow_iframe_requests
-  protect_from_forgery(with: :exception)
+  protect_from_forgery(with: :exception, prepend: true)
  rescue_from Pundit::NotAuthorizedError, with: :render_not_authorized

  def current_user
@ -14,11 +14,8 @@ class ApplicationController < ActionController::Base
    @current_user ||= ExternalUser.find_by(id: session[:external_user_id]) || login_from_session || login_from_other_sources
  end

-  def help
-  end
-
  def render_not_authorized
-    redirect_to(:root, alert: t('application.not_authorized'))
+    redirect_to(request.referrer || :root, alert: t('application.not_authorized'))
  end
  private :render_not_authorized

--- a/app/controllers/code_ocean/errors_controller.rb
+++ b/app/controllers/code_ocean/errors_controller.rb
@ -0,0 +1,45 @@
+module CodeOcean
+  class ErrorsController < ApplicationController
+    before_action :set_execution_environment
+
+    def authorize!
+      authorize(@error || @errors)
+    end
+    private :authorize!
+
+    def create
+      @error = CodeOcean::Error.new(error_params)
+      authorize!
+      hint = Whistleblower.new(execution_environment: @error.execution_environment).generate_hint(@error.message)
+      respond_to do |format|
+        format.json do
+          if hint
+            render(json: {hint: hint})
+          else
+            head (@error.save ? :created : :unprocessable_entity)
+          end
+        end
+      end
+    end
+
+    def error_params
+      params[:error].permit(:message, :submission_id).merge(execution_environment_id: @execution_environment.id) if params[:error].present?
+    end
+    private :error_params
+
+    def index
+      @errors = CodeOcean::Error.for_execution_environment(@execution_environment).grouped_by_message.paginate(page: params[:page])
+      authorize!
+    end
+
+    def set_execution_environment
+      @execution_environment = ExecutionEnvironment.find(params[:execution_environment_id])
+    end
+    private :set_execution_environment
+
+    def show
+      @error = CodeOcean::Error.find(params[:id])
+      authorize!
+    end
+  end
+end
--- a/app/controllers/code_ocean/files_controller.rb
+++ b/app/controllers/code_ocean/files_controller.rb
@ -41,7 +41,7 @@ module CodeOcean
    end

    def file_params
-      params[:code_ocean_file].permit(file_attributes).merge(context_type: 'Submission', role: 'user_defined_file')
+      params[:code_ocean_file].permit(file_attributes).merge(context_type: 'Submission', role: 'user_defined_file') if params[:code_ocean_file].present?
    end
    private :file_params
  end
--- a/app/controllers/concerns/.keep
+++ b/app/controllers/concerns/.keep
--- a/app/controllers/concerns/lti.rb
+++ b/app/controllers/concerns/lti.rb
@ -23,9 +23,9 @@ module Lti
      session.delete(:consumer_id)
      session.delete(:external_user_id)
    else
-      LtiParameter.destroy_all(consumers_id: consumer_id,
-                               external_users_id: user_id,
-                               exercises_id: exercise_id)
+      LtiParameter.where(consumers_id: consumer_id,
+                         external_users_id: user_id,
+                         exercises_id: exercise_id).destroy_all
    end
  end
  private :clear_lti_session_data
@ -138,7 +138,7 @@ module Lti
                                                    external_users_id: @current_user.id,
                                                    exercises_id: @exercise.id)

-    lti_parameters.lti_parameters = options[:parameters].slice(*SESSION_PARAMETERS).to_json
+    lti_parameters.lti_parameters = options[:parameters].slice(*SESSION_PARAMETERS).permit!.to_h
    lti_parameters.save!
    @lti_parameters = lti_parameters

--- a/app/controllers/concerns/remote_evaluation_parameters.rb
+++ b/app/controllers/concerns/remote_evaluation_parameters.rb
@ -2,7 +2,7 @@ module RemoteEvaluationParameters
  include FileParameters

  def remote_evaluation_params
-    remote_evaluation_params = params[:remote_evaluation].permit(:validation_token, files_attributes: file_attributes)
+    remote_evaluation_params = params[:remote_evaluation].permit(:validation_token, files_attributes: file_attributes) if params[:remote_evaluation].present?
  end
  private :remote_evaluation_params
 end
--- a/app/controllers/concerns/submission_parameters.rb
+++ b/app/controllers/concerns/submission_parameters.rb
@ -16,7 +16,7 @@ module SubmissionParameters
      current_user_id = current_user.id
      current_user_class_name = current_user.class.name
    end
-    submission_params = params[:submission].permit(:cause, :exercise_id, files_attributes: file_attributes).merge(user_id: current_user_id, user_type: current_user_class_name)
+    submission_params = params[:submission].present? ? params[:submission].permit(:cause, :exercise_id, files_attributes: file_attributes).merge(user_id: current_user_id, user_type: current_user_class_name) : {}
    reject_illegal_file_attributes!(submission_params)
    submission_params
  end
--- a/app/controllers/consumers_controller.rb
+++ b/app/controllers/consumers_controller.rb
@ -22,7 +22,7 @@ class ConsumersController < ApplicationController
  end

  def consumer_params
-    params[:consumer].permit(:name, :oauth_key, :oauth_secret)
+    params[:consumer].permit(:name, :oauth_key, :oauth_secret) if params[:consumer].present?
  end
  private :consumer_params

--- a/app/controllers/error_template_attributes_controller.rb
+++ b/app/controllers/error_template_attributes_controller.rb
@ -81,6 +81,6 @@ class ErrorTemplateAttributesController < ApplicationController

    # Never trust parameters from the scary internet, only allow the white list through.
    def error_template_attribute_params
-      params[:error_template_attribute].permit(:key, :description, :regex, :important)
+      params[:error_template_attribute].permit(:key, :description, :regex, :important) if params[:error_template_attribute].present?
    end
 end
--- a/app/controllers/error_templates_controller.rb
+++ b/app/controllers/error_templates_controller.rb
@ -99,6 +99,6 @@ class ErrorTemplatesController < ApplicationController

    # Never trust parameters from the scary internet, only allow the white list through.
    def error_template_params
-      params[:error_template].permit(:name, :execution_environment_id, :signature, :description, :hint)
+      params[:error_template].permit(:name, :execution_environment_id, :signature, :description, :hint) if params[:error_template].present?
    end
 end
--- a/app/controllers/errors_controller.rb
+++ b/app/controllers/errors_controller.rb
@ -1,43 +0,0 @@
-class ErrorsController < ApplicationController
-  before_action :set_execution_environment
-
-  def authorize!
-    authorize(@error || @errors)
-  end
-  private :authorize!
-
-  def create
-    @error = Error.new(error_params)
-    authorize!
-    hint = Whistleblower.new(execution_environment: @error.execution_environment).generate_hint(@error.message)
-    respond_to do |format|
-      format.json do
-        if hint
-          render(json: {hint: hint})
-        else
-          render(nothing: true, status: @error.save ? :created : :unprocessable_entity)
-        end
-      end
-    end
-  end
-
-  def error_params
-    params[:error].permit(:message, :submission_id).merge(execution_environment_id: @execution_environment.id)
-  end
-  private :error_params
-
-  def index
-    @errors = Error.for_execution_environment(@execution_environment).grouped_by_message.paginate(page: params[:page])
-    authorize!
-  end
-
-  def set_execution_environment
-    @execution_environment = ExecutionEnvironment.find(params[:execution_environment_id])
-  end
-  private :set_execution_environment
-
-  def show
-    @error = Error.find(params[:id])
-    authorize!
-  end
-end
--- a/app/controllers/execution_environments_controller.rb
+++ b/app/controllers/execution_environments_controller.rb
@ -86,11 +86,11 @@ class ExecutionEnvironmentsController < ApplicationController
    working_time_statistics = {}
    user_statistics = {}

-    ActiveRecord::Base.connection.execute(working_time_query).each do |tuple|
+    ApplicationRecord.connection.execute(working_time_query).each do |tuple|
      working_time_statistics[tuple["exercise_id"].to_i] = tuple
    end

-    ActiveRecord::Base.connection.execute(user_query).each do |tuple|
+    ApplicationRecord.connection.execute(user_query).each do |tuple|
      user_statistics[tuple["exercise_id"].to_i] = tuple
    end

@ -101,7 +101,7 @@ class ExecutionEnvironmentsController < ApplicationController
  end

  def execution_environment_params
-    params[:execution_environment].permit(:docker_image, :exposed_ports, :editor_mode, :file_extension, :file_type_id, :help, :indent_size, :memory_limit, :name, :network_enabled, :permitted_execution_time, :pool_size, :run_command, :test_command, :testing_framework).merge(user_id: current_user.id, user_type: current_user.class.name)
+    params[:execution_environment].permit(:docker_image, :exposed_ports, :editor_mode, :file_extension, :file_type_id, :help, :indent_size, :memory_limit, :name, :network_enabled, :permitted_execution_time, :pool_size, :run_command, :test_command, :testing_framework).merge(user_id: current_user.id, user_type: current_user.class.name) if params[:execution_environment].present?
  end
  private :execution_environment_params

--- a/app/controllers/exercise_collections_controller.rb
+++ b/app/controllers/exercise_collections_controller.rb
@ -51,7 +51,7 @@ class ExerciseCollectionsController < ApplicationController
  end

  def exercise_collection_params
-    sanitized_params = params[:exercise_collection].permit(:name, :use_anomaly_detection, :user_id, :user_type, :exercise_ids => []).merge(user_type: InternalUser.name)
+    sanitized_params = params[:exercise_collection].present? ? params[:exercise_collection].permit(:name, :use_anomaly_detection, :user_id, :user_type, :exercise_ids => []).merge(user_type: InternalUser.name) : {}
    sanitized_params[:exercise_ids] = sanitized_params[:exercise_ids].reject {|v| v.nil? or v == ''}
    sanitized_params.tap {|p| p[:exercise_collection_items] = p[:exercise_ids].map.with_index {|_id, index| ExerciseCollectionItem.find_or_create_by(exercise_id: _id, exercise_collection_id: @exercise_collection.id, position: index)}; p.delete(:exercise_ids)}
  end
--- a/app/controllers/exercises_controller.rb
+++ b/app/controllers/exercises_controller.rb
@ -12,9 +12,9 @@ class ExercisesController < ApplicationController
  before_action :set_file_types, only: [:create, :edit, :new, :update]
  before_action :set_course_token, only: [:implement]

-  skip_before_filter :verify_authenticity_token, only: [:import_proforma_xml]
+  skip_before_action :verify_authenticity_token, only: [:import_proforma_xml]
  skip_after_action :verify_authorized, only: [:import_proforma_xml]
-  skip_after_action :verify_policy_scoped, only: [:import_proforma_xml]
+  skip_after_action :verify_policy_scoped, only: [:import_proforma_xml], raise: false

  def authorize!
    authorize(@exercise || @exercises)
@ -77,7 +77,7 @@ class ExercisesController < ApplicationController
  def create
    @exercise = Exercise.new(exercise_params)
    collect_set_and_unset_exercise_tags
-    myparam = exercise_params
+    myparam = exercise_params.present? ? exercise_params : { }
    checked_exercise_tags = @exercise_tags.select { | et | myparam[:tag_ids].include? et.tag.id.to_s }
    removed_exercise_tags = @exercise_tags.reject { | et | myparam[:tag_ids].include? et.tag.id.to_s }

@ -160,19 +160,21 @@ class ExercisesController < ApplicationController
  private :user_by_code_harbor_token

  def exercise_params
-    params[:exercise].permit(:description, :execution_environment_id, :file_id, :instructions, :public, :hide_file_tree, :allow_file_creation, :allow_auto_completion, :title, :expected_difficulty, files_attributes: file_attributes, :tag_ids => []).merge(user_id: current_user.id, user_type: current_user.class.name)
+    params[:exercise].permit(:description, :execution_environment_id, :file_id, :instructions, :public, :hide_file_tree, :allow_file_creation, :allow_auto_completion, :title, :expected_difficulty, files_attributes: file_attributes, :tag_ids => []).merge(user_id: current_user.id, user_type: current_user.class.name) if params[:exercise].present?
  end
  private :exercise_params

  def handle_file_uploads
-    exercise_params[:files_attributes].try(:each) do |index, file_attributes|
-      if file_attributes[:content].respond_to?(:read)
-        file_params = params[:exercise][:files_attributes][index]
-        if FileType.find_by(id: file_attributes[:file_type_id]).try(:binary?)
-          file_params[:content] = nil
-          file_params[:native_file] = file_attributes[:content]
-        else
-          file_params[:content] = file_attributes[:content].read
+    if exercise_params
+      exercise_params[:files_attributes].try(:each) do |index, file_attributes|
+        if file_attributes[:content].respond_to?(:read)
+          file_params = params[:exercise][:files_attributes][index]
+          if FileType.find_by(id: file_attributes[:file_type_id]).try(:binary?)
+            file_params[:content] = nil
+            file_params[:native_file] = file_attributes[:content]
+          else
+            file_params[:content] = file_attributes[:content].read
+          end
        end
      end
    end
@ -185,28 +187,8 @@ class ExercisesController < ApplicationController
    count_interventions_today = UserExerciseIntervention.where(user: current_user).where("created_at >= ?", Time.zone.now.beginning_of_day).count
    user_got_intervention_in_exercise = UserExerciseIntervention.where(user: current_user, exercise: @exercise).size >= max_intervention_count_per_exercise
    user_got_enough_interventions = count_interventions_today >= max_intervention_count_per_day or user_got_intervention_in_exercise
-    @is_experimental_course = @course_token and experimental_course?(@course_token)
-
-    @experiment_group = UserGroupSeparator.getInterventionGroup(current_user)
-
-    showInterventions = (@is_experimental_course and not user_solved_exercise and not user_got_enough_interventions) ? "true" : "false"
-
-    case @experiment_group
-      when :rfc_intervention_stale_rfc
-        @show_rfc_interventions = showInterventions
-      when :break_intervention_stale_rfc
-        @show_break_interventions = showInterventions
-      when :no_intervention_stale_rfc
-      when :no_intervention_hide_rfc
-        @hide_rfc_button = "true"
-      when :break_intervention_show_rfc
-        @show_break_interventions = showInterventions
-      when :no_intervention_show_rfc
-      when :rfc_intervention_show_rfc
-        @show_rfc_interventions = showInterventions
-    end
-

+    @show_rfc_interventions = (not user_solved_exercise and not user_got_enough_interventions).to_s


    @search = Search.new
@ -364,7 +346,7 @@ class ExercisesController < ApplicationController
      query = "SELECT user_id, MAX(score) AS maximum_score, COUNT(id) AS runs
              FROM submissions WHERE exercise_id = #{@exercise.id} GROUP BY
              user_id;"
-      ActiveRecord::Base.connection.execute(query).each do |tuple|
+      ApplicationRecord.connection.execute(query).each do |tuple|
        user_statistics[tuple["user_id"].to_i] = tuple
      end
      render locals: {
@ -428,11 +410,6 @@ class ExercisesController < ApplicationController
          return
        end

-        if @is_experimental_course and (@rfc_group == :hide_rfc)
-          redirect_to_lti_return_path
-          return
-        end
-
        rfc = @submission.own_unsolved_rfc
        if rfc
          # set a message that informs the user that his own RFC should be closed.
--- a/app/controllers/external_users_controller.rb
+++ b/app/controllers/external_users_controller.rb
@ -57,7 +57,7 @@ class ExternalUsersController < ApplicationController

    statistics = {}

-    ActiveRecord::Base.connection.execute(working_time_query(params[:tag])).each do |tuple|
+    ApplicationRecord.connection.execute(working_time_query(params[:tag])).each do |tuple|
      statistics[tuple["exercise_id"].to_i] = tuple
    end

--- a/app/controllers/file_templates_controller.rb
+++ b/app/controllers/file_templates_controller.rb
@ -89,6 +89,6 @@ class FileTemplatesController < ApplicationController

    # Never trust parameters from the scary internet, only allow the white list through.
    def file_template_params
-      params[:file_template].permit(:name, :file_type_id, :content)
+      params[:file_template].permit(:name, :file_type_id, :content) if params[:file_template].present?
    end
 end
--- a/app/controllers/file_types_controller.rb
+++ b/app/controllers/file_types_controller.rb
@ -23,7 +23,7 @@ class FileTypesController < ApplicationController
  end

  def file_type_params
-    params[:file_type].permit(:binary, :editor_mode, :executable, :file_extension, :name, :indent_size, :renderable).merge(user_id: current_user.id, user_type: current_user.class.name)
+    params[:file_type].permit(:binary, :editor_mode, :executable, :file_extension, :name, :indent_size, :renderable).merge(user_id: current_user.id, user_type: current_user.class.name) if params[:file_type].present?
  end
  private :file_type_params

@ -38,7 +38,7 @@ class FileTypesController < ApplicationController
  end

  def set_editor_modes
-    @editor_modes = Dir.glob('vendor/assets/javascripts/ace/mode-*.js').map do |filename|
+    @editor_modes = Dir.glob('vendor/assets/javascripts/ace/mode-*.js').sort.map do |filename|
      name = filename.gsub(/\w+\/|mode-|.js$/, '')
      [name, "ace/mode/#{name}"]
    end
--- a/app/controllers/hints_controller.rb
+++ b/app/controllers/hints_controller.rb
@ -23,7 +23,7 @@ class HintsController < ApplicationController
  end

  def hint_params
-    params[:hint].permit(:locale, :message, :name, :regular_expression).merge(execution_environment_id: @execution_environment.id)
+    params[:hint].permit(:locale, :message, :name, :regular_expression).merge(execution_environment_id: @execution_environment.id) if params[:hint].present?
  end
  private :hint_params

--- a/app/controllers/internal_users_controller.rb
+++ b/app/controllers/internal_users_controller.rb
@ -21,7 +21,7 @@ class InternalUsersController < ApplicationController
      if @user.update(params[:internal_user].permit(:password, :password_confirmation))
        @user.change_password!(params[:internal_user][:password])
        format.html { redirect_to(sign_in_path, notice: t('.success')) }
-        format.json { render(nothing: true, status: :ok) }
+        format.json { head :ok }
      else
        respond_with_invalid_object(format, object: @user, template: :reset_password)
      end
@ -66,7 +66,7 @@ class InternalUsersController < ApplicationController
  end

  def internal_user_params
-    params[:internal_user].permit(:consumer_id, :email, :name, :role)
+    params[:internal_user].permit(:consumer_id, :email, :name, :role) if params[:internal_user].present?
  end
  private :internal_user_params

@ -105,7 +105,7 @@ class InternalUsersController < ApplicationController
      if @user.update(params[:internal_user].permit(:password, :password_confirmation))
        @user.activate!
        format.html { redirect_to(sign_in_path, notice: t('.success')) }
-        format.json { render(nothing: true, status: :ok) }
+        format.json { head :ok }
      else
        respond_with_invalid_object(format, object: @user, template: :activate)
      end
--- a/app/controllers/interventions_controller.rb
+++ b/app/controllers/interventions_controller.rb
@ -22,7 +22,7 @@ class InterventionsController < ApplicationController
  end

  def intervention_params
-    params[:intervention].permit(:name)
+    params[:intervention].permit(:name) if params[:intervention].present?
  end
  private :intervention_params

--- a/app/controllers/proxy_exercises_controller.rb
+++ b/app/controllers/proxy_exercises_controller.rb
@ -39,7 +39,7 @@ class ProxyExercisesController < ApplicationController
  end

  def proxy_exercise_params
-    params[:proxy_exercise].permit(:description, :title, :exercise_ids  => [])
+    params[:proxy_exercise].permit(:description, :title, :exercise_ids  => []) if params[:proxy_exercise].present?
  end
  private :proxy_exercise_params

--- a/app/controllers/remote_evaluation_controller.rb
+++ b/app/controllers/remote_evaluation_controller.rb
@ -15,14 +15,12 @@ class RemoteEvaluationController < ApplicationController

    # todo extra: validiere, ob files wirklich zur Übung gehören (wenn allowNewFiles-flag nicht gesetzt ist)
    if (remote_evaluation_mapping = RemoteEvaluationMapping.find_by(:validation_token => validation_token))
-      puts remote_evaluation_mapping.exercise_id
-      puts remote_evaluation_mapping.user_id

      _params = remote_evaluation_params.except(:validation_token)
      _params[:exercise_id] = remote_evaluation_mapping.exercise_id
      _params[:user_id] = remote_evaluation_mapping.user_id
      _params[:cause] = "remoteAssess"
-      _params[:user_type] = "ExternalUser"
+      _params[:user_type] = remote_evaluation_mapping.user_type

      @submission = Submission.create(_params)
      render json: score_submission(@submission)
--- a/app/controllers/submissions_controller.rb
+++ b/app/controllers/submissions_controller.rb
@ -115,7 +115,7 @@ class SubmissionsController < ApplicationController
    if @file.native_file?
      send_file(@file.native_file.path, disposition: 'inline')
    else
-      render(text: @file.content)
+      render(plain: @file.content)
    end
  end

@ -140,7 +140,7 @@ class SubmissionsController < ApplicationController
      # probably add:
      # ensure
      #   #guarantee that the thread is releasing the DB connection after it is done
-      #   ActiveRecord::Base.connectionpool.releaseconnection
+      #   ApplicationRecord.connectionpool.releaseconnection
      # end
      Thread.new { EventMachine.run } unless EventMachine.reactor_running? && EventMachine.reactor_thread.alive?

@ -329,7 +329,7 @@ class SubmissionsController < ApplicationController

  def set_file
    @file = @files.detect { |file| file.name_with_extension == params[:filename] }
-    render(nothing: true, status: 404) unless @file
+    head :not_found unless @file
  end
  private :set_file

@ -362,11 +362,11 @@ class SubmissionsController < ApplicationController
    DockerClient.destroy_container(container)
  rescue Docker::Error::NotFoundError
  ensure
-    render(nothing: true)
+    head :ok
  end

  def store_error(stderr)
-    ::Error.create(submission_id: @submission.id, execution_environment_id: @submission.execution_environment.id, message: stderr)
+    CodeOcean::Error.create(submission_id: @submission.id, execution_environment_id: @submission.execution_environment.id, message: stderr)
  end
  private :store_error

@ -398,13 +398,13 @@ class SubmissionsController < ApplicationController
  private :with_server_sent_events

  def create_remote_evaluation_mapping
-    user_id = @submission.user_id
+    user = @submission.user
    exercise_id = @submission.exercise_id

-    remote_evaluation_mapping = RemoteEvaluationMapping.create(:user_id => user_id, :exercise_id => exercise_id)
+    remote_evaluation_mapping = RemoteEvaluationMapping.create(user: user, exercise_id: exercise_id)

    # create .co file
-    path = "tmp/" + user_id.to_s + ".co"
+    path = "tmp/" + user.id.to_s + ".co"
    # parse validation token
    content = "#{remote_evaluation_mapping.validation_token}\n"
    # parse remote request url
--- a/app/controllers/subscriptions_controller.rb
+++ b/app/controllers/subscriptions_controller.rb
@ -56,7 +56,7 @@ class SubscriptionsController < ApplicationController
  def subscription_params
    current_user_id = current_user.try(:id)
    current_user_class_name = current_user.try(:class).try(:name)
-    params[:subscription].permit(:request_for_comment_id, :subscription_type).merge(user_id: current_user_id, user_type: current_user_class_name, deleted: false)
+    params[:subscription].permit(:request_for_comment_id, :subscription_type).merge(user_id: current_user_id, user_type: current_user_class_name, deleted: false) if params[:subscription].present?
  end
  private :subscription_params
 end
--- a/app/controllers/tags_controller.rb
+++ b/app/controllers/tags_controller.rb
@ -22,7 +22,7 @@ class TagsController < ApplicationController
  end

  def tag_params
-    params[:tag].permit(:name)
+    params[:tag].permit(:name) if params[:tag].present?
  end
  private :tag_params

--- a/app/controllers/user_exercise_feedbacks_controller.rb
+++ b/app/controllers/user_exercise_feedbacks_controller.rb
@ -1,8 +1,7 @@
 class UserExerciseFeedbacksController < ApplicationController
  include CommonBehavior

-  before_action :set_user_exercise_feedback, only: [:edit, :update]
-  before_action :set_user_exercise_feedback_by_id, only: [:show, :destroy]
+  before_action :set_user_exercise_feedback, only: [:edit, :update, :show, :destroy]

  def comment_presets
    [[0,t('user_exercise_feedback.difficulty_easy')],
@ -103,16 +102,12 @@ class UserExerciseFeedbacksController < ApplicationController
  end

  def set_user_exercise_feedback
-    @exercise = Exercise.find(params[:user_exercise_feedback][:exercise_id])
-    @uef = UserExerciseFeedback.find_by(exercise_id: params[:user_exercise_feedback][:exercise_id], user: current_user)
-  end
-
-  def set_user_exercise_feedback_by_id
    @uef = UserExerciseFeedback.find(params[:id])
+    @exercise = @uef.exercise
  end

  def uef_params
-    params[:user_exercise_feedback].permit(:feedback_text, :difficulty, :exercise_id, :user_estimated_worktime).merge(user_id: current_user.id, user_type: current_user.class.name)
+    params[:user_exercise_feedback].permit(:feedback_text, :difficulty, :exercise_id, :user_estimated_worktime).merge(user_id: current_user.id, user_type: current_user.class.name) if params[:user_exercise_feedback].present?
  end

  def validate_inputs(uef_params)
--- a/app/helpers/lti_helper.rb
+++ b/app/helpers/lti_helper.rb
@ -1,3 +1,5 @@
+require 'oauth/request_proxy/action_controller_request' # Rails 5 changed `Rack::Request` to `ActionDispatch::Request`
+
 module LtiHelper
  def lti_outcome_service?(exercise_id, external_user_id, consumer_id)
    return false if external_user_id == '' || consumer_id == ''
--- a/app/helpers/pagedown_form_builder.rb
+++ b/app/helpers/pagedown_form_builder.rb
@ -0,0 +1,42 @@
+# frozen_string_literal: true
+
+class PagedownFormBuilder < ActionView::Helpers::FormBuilder
+  def pagedown(method, args)
+    # Adopt simple form builder to work with form_for
+    @attribute_name = method
+    @input_html_options = args[:input_html]
+
+    @template.capture do
+      @template.concat wmd_button_bar
+      @template.concat wmd_textarea
+      @template.concat wmd_preview if show_wmd_preview?
+    end
+  end
+
+  private
+
+  def wmd_button_bar
+    @template.content_tag :div, nil, id: "wmd-button-bar-#{base_id}"
+  end
+
+  def wmd_textarea
+    @template.text_area @object_name, @attribute_name,
+                       **@input_html_options,
+                       class: 'form-control wmd-input',
+                       id: "wmd-input-#{base_id}"
+  end
+
+  def wmd_preview
+    @template.content_tag :div, nil,
+                         class: 'wmd-preview',
+                         id: "wmd-preview-#{base_id}"
+  end
+
+  def show_wmd_preview?
+    @input_html_options[:preview].present?
+  end
+
+  def base_id
+    options[:pagedown_id_suffix] || @attribute_name
+  end
+end
--- a/app/helpers/request_for_comments_helper.rb
+++ b/app/helpers/request_for_comments_helper.rb
@ -1,2 +0,0 @@
-module RequestForCommentsHelper
-end
--- a/app/javascript/packs/application.js
+++ b/app/javascript/packs/application.js
@ -0,0 +1,36 @@
+/* eslint no-console:0 */
+// This file is automatically compiled by Webpack, along with any other files
+// present in this directory. You're encouraged to place your actual application logic in
+// a relevant structure within app/javascript and only use these pack files to reference
+// that code so it'll be compiled.
+//
+// To reference this file, add <%= javascript_pack_tag 'application' %> to the appropriate
+// layout file, like app/views/layouts/application.html.slim
+
+// JS
+import 'jquery'
+import 'bootstrap/dist/js/bootstrap.bundle.min';
+import 'chosen-js/chosen.jquery';
+import 'jstree';
+import 'underscore';
+window._ = _; // Publish underscore's `_` in global namespace
+
+// CSS
+import 'chosen-js/chosen.css';
+import 'jstree/dist/themes/default/style.min.css';
+
+// custom jquery-ui library for minimal mouse interaction support
+import 'jquery-ui/ui/widget'
+import 'jquery-ui/ui/data'
+import 'jquery-ui/ui/disable-selection'
+import 'jquery-ui/ui/scroll-parent'
+import 'jquery-ui/ui/widgets/draggable'
+import 'jquery-ui/ui/widgets/droppable'
+import 'jquery-ui/ui/widgets/resizable'
+import 'jquery-ui/ui/widgets/selectable'
+import 'jquery-ui/ui/widgets/sortable'
+import 'jquery-ui/themes/base/draggable.css'
+import 'jquery-ui/themes/base/core.css'
+import 'jquery-ui/themes/base/resizable.css'
+import 'jquery-ui/themes/base/selectable.css'
+import 'jquery-ui/themes/base/sortable.css'
--- a/app/javascript/packs/d3-tip.js
+++ b/app/javascript/packs/d3-tip.js
@ -0,0 +1,12 @@
+/* eslint no-console:0 */
+// This file is automatically compiled by Webpack, along with any other files
+// present in this directory. You're encouraged to place your actual application logic in
+// a relevant structure within app/javascript and only use these pack files to reference
+// that code so it'll be compiled.
+//
+// To reference this file, add <%= javascript_pack_tag 'application' %> to the appropriate
+// layout file, like app/views/layouts/application.html.slim
+
+// JS
+import d3Tip from 'd3-tip'
+window.d3.tip = d3Tip;
--- a/app/javascript/packs/highlight.js
+++ b/app/javascript/packs/highlight.js
@ -0,0 +1,15 @@
+/* eslint no-console:0 */
+// This file is automatically compiled by Webpack, along with any other files
+// present in this directory. You're encouraged to place your actual application logic in
+// a relevant structure within app/javascript and only use these pack files to reference
+// that code so it'll be compiled.
+//
+// To reference this file, add <%= javascript_pack_tag 'application' %> to the appropriate
+// layout file, like app/views/layouts/application.html.slim
+
+// JS
+import hljs from 'highlight.js'
+window.hljs = hljs;
+
+// CSS
+import 'highlight.js/styles/default.css'
--- a/app/javascript/packs/stylesheets.scss
+++ b/app/javascript/packs/stylesheets.scss
@ -0,0 +1,16 @@
+/* eslint no-console:0 */
+// This file is automatically compiled by Webpack, along with any other files
+// present in this directory. You're encouraged to place your actual application logic in
+// a relevant structure within app/javascript and only use these pack files to reference
+// that code so it'll be compiled.
+//
+// To reference this file, add <%= stylesheet_pack_tag 'stylesheets' %> to the appropriate
+// layout file, like app/views/layouts/application.html.slim
+
+@import '~bootswatch/dist/yeti/variables';
+@import '~bootstrap/scss/bootstrap';
+@import '~bootswatch/dist/yeti/bootswatch';
+$fa-font-path: '~font-awesome/fonts';
+@import '~font-awesome/scss/font-awesome';
+$opensans-path: '~opensans-webkit/fonts/';
+@import '~opensans-webkit/src/sass/open-sans';
--- a/app/javascript/packs/vis.js
+++ b/app/javascript/packs/vis.js
@ -0,0 +1,15 @@
+/* eslint no-console:0 */
+// This file is automatically compiled by Webpack, along with any other files
+// present in this directory. You're encouraged to place your actual application logic in
+// a relevant structure within app/javascript and only use these pack files to reference
+// that code so it'll be compiled.
+//
+// To reference this file, add <%= javascript_pack_tag 'application' %> to the appropriate
+// layout file, like app/views/layouts/application.html.slim
+
+// JS
+import 'vis'
+window.vis = vis;
+
+// CSS
+import 'vis/dist/vis.min.css'
--- a/app/mailers/.keep
+++ b/app/mailers/.keep
--- a/app/models/.keep
+++ b/app/models/.keep
--- a/app/models/anomaly_notification.rb
+++ b/app/models/anomaly_notification.rb
@ -1,4 +1,4 @@
-class AnomalyNotification < ActiveRecord::Base
+class AnomalyNotification < ApplicationRecord
  belongs_to :user, polymorphic: true
  belongs_to :exercise
  belongs_to :exercise_collection
--- a/app/models/application_record.rb
+++ b/app/models/application_record.rb
@ -0,0 +1,3 @@
+class ApplicationRecord < ActiveRecord::Base
+  self.abstract_class = true
+end
--- a/app/models/code_harbor_link.rb
+++ b/app/models/code_harbor_link.rb
@ -1,4 +1,4 @@
-class CodeHarborLink < ActiveRecord::Base
+class CodeHarborLink < ApplicationRecord
  validates :oauth2token, presence: true
  validates :user_id, presence: true

--- a/app/models/code_ocean/error.rb
+++ b/app/models/code_ocean/error.rb
@ -0,0 +1,19 @@
+module CodeOcean
+  class Error < ApplicationRecord
+    belongs_to :execution_environment
+
+    scope :for_execution_environment, ->(execution_environment) { where(execution_environment_id: execution_environment.id) }
+    scope :grouped_by_message, -> { select('MAX(created_at) AS created_at, MAX(id) AS id, message, COUNT(id) AS count').group(:message).order('count DESC') }
+
+    validates :execution_environment_id, presence: true
+    validates :message, presence: true
+
+    def self.nested_resource?
+      true
+    end
+
+    def to_s
+      id.to_s
+    end
+  end
+end
--- a/app/models/code_ocean/file.rb
+++ b/app/models/code_ocean/file.rb
@ -15,7 +15,7 @@ module CodeOcean
    end
  end

-  class File < ActiveRecord::Base
+  class File < ApplicationRecord
    include DefaultValues

    DEFAULT_WEIGHT = 1.0
@ -28,12 +28,11 @@ module CodeOcean
    before_validation :set_ancestor_values, if: :incomplete_descendent?

    belongs_to :context, polymorphic: true
-    belongs_to :execution_environment
-    belongs_to :file
+    belongs_to :file, class_name: 'CodeOcean::File', optional: true # This is only required for submissions and is validated below
    alias_method :ancestor, :file
    belongs_to :file_type

-    has_many :files
+    has_many :files, class_name: 'CodeOcean::File'
    has_many :testruns
    has_many :comments
    alias_method :descendants, :files
@ -47,6 +46,8 @@ module CodeOcean
      scope :"#{role}s", -> { where(role: role) }
    end

+    default_scope { order(name: :asc) }
+
    validates :feedback_message, if: :teacher_defined_test?, presence: true
    validates :feedback_message, absence: true, unless: :teacher_defined_test?
    validates :file_type_id, presence: true
@ -57,6 +58,7 @@ module CodeOcean
    validates :role, inclusion: {in: ROLES}
    validates :weight, if: :teacher_defined_test?, numericality: true, presence: true
    validates :weight, absence: true, unless: :teacher_defined_test?
+    validates :file, presence: true if :context.is_a?(Submission)

    validates_with FileNameValidator, fields: [:name, :path, :file_type_id]

@ -78,6 +80,14 @@ module CodeOcean
    end
    private :content_present?

+    def filepath
+      if path.present?
+        ::File.join(path, name_with_extension)
+      else
+        name_with_extension
+      end
+    end
+
    def hash_content
      self.hashed_content = Digest::MD5.new.hexdigest(file_type.try(:binary?) ? ::File.new(native_file.file.path, 'r').read : content)
    end
--- a/app/models/comment.rb
+++ b/app/models/comment.rb
@ -1,4 +1,4 @@
-class Comment < ActiveRecord::Base
+class Comment < ApplicationRecord
  # inherit the creation module: encapsulates that this is a polymorphic user, offers some aliases and makes sure that all necessary attributes are set.
  include Creation
  attr_accessor :username, :date, :updated, :editable
--- a/app/models/concerns/.keep
+++ b/app/models/concerns/.keep
--- a/app/models/consumer.rb
+++ b/app/models/consumer.rb
@ -1,4 +1,4 @@
-class Consumer < ActiveRecord::Base
+class Consumer < ApplicationRecord
  has_many :users

  scope :with_users, -> { where('id IN (SELECT consumer_id FROM internal_users)') }
--- a/app/models/error.rb
+++ b/app/models/error.rb
@ -1,13 +0,0 @@
-class Error < ActiveRecord::Base
-  belongs_to :execution_environment
-
-  scope :for_execution_environment, ->(execution_environment) { where(execution_environment_id: execution_environment.id) }
-  scope :grouped_by_message, -> { select('MAX(created_at) AS created_at, MAX(id) AS id, message, COUNT(id) AS count').group(:message).order('count DESC') }
-
-  validates :execution_environment_id, presence: true
-  validates :message, presence: true
-
-  def self.nested_resource?
-    true
-  end
-end
--- a/app/models/error_template.rb
+++ b/app/models/error_template.rb
@ -1,8 +1,8 @@
-class ErrorTemplate < ActiveRecord::Base
+class ErrorTemplate < ApplicationRecord
  belongs_to :execution_environment
  has_and_belongs_to_many :error_template_attributes

  def to_s
-    "#{id} [#{name}]"
+    name
  end
 end
--- a/app/models/error_template_attribute.rb
+++ b/app/models/error_template_attribute.rb
@ -1,7 +1,7 @@
-class ErrorTemplateAttribute < ActiveRecord::Base
+class ErrorTemplateAttribute < ApplicationRecord
  has_and_belongs_to_many :error_template

  def to_s
-    "#{id} [#{key}]"
+    key
  end
 end
--- a/app/models/event.rb
+++ b/app/models/event.rb
@ -1,7 +1,7 @@
-class Event < ActiveRecord::Base
+class Event < ApplicationRecord
  belongs_to :user, polymorphic: true
  belongs_to :exercise
-  belongs_to :file
+  belongs_to :file, class_name: 'CodeOcean::File'

  validates :category, presence: true
  validates :data, presence: true
--- a/app/models/execution_environment.rb
+++ b/app/models/execution_environment.rb
@ -1,6 +1,6 @@
 require File.expand_path('../../../lib/active_model/validations/boolean_presence_validator', __FILE__)

-class ExecutionEnvironment < ActiveRecord::Base
+class ExecutionEnvironment < ApplicationRecord
  include Creation
  include DefaultValues

--- a/Show More
+++ b/Show More