Add sentry for error tracing

Gemfile

@@ -3,7 +3,6 @@ source 'https://rubygems.org'
 gem 'bcrypt'
 gem 'bootstrap-will_paginate'
 gem 'carrierwave'
-gem 'concurrent-ruby'
 gem 'docker-api', require: 'docker'
 gem 'factory_bot_rails'
 gem 'forgery'
@@ -12,7 +11,6 @@ gem 'jbuilder'
 gem 'jquery-rails'
 gem 'ims-lti', '< 2.0.0'
 gem 'kramdown'
-gem 'newrelic_rpm'
 gem 'pg'
 gem 'pry-byebug'
 gem 'puma'
@@ -35,12 +33,17 @@ gem 'nokogiri'
 gem 'webpacker'
 gem 'rest-client'
 gem 'rubyzip'
-gem 'mnemosyne-ruby'
 gem 'faraday'
 gem 'proforma', git: 'https://github.com/openHPI/proforma.git', tag: 'v0.4'
 gem 'whenever', require: false
 gem 'rails-timeago'
 
+# Error Tracing
+gem 'concurrent-ruby'
+gem 'mnemosyne-ruby'
+gem 'newrelic_rpm'
+gem 'sentry-raven'
+
 group :development, :staging do
   gem 'bootsnap', require: false
   gem 'listen'

Gemfile.lock

@@ -151,7 +151,7 @@ GEM
     factory_bot_rails (5.1.1)
       factory_bot (~> 5.1.0)
       railties (>= 4.2.0)
-    faraday (1.0.0)
+    faraday (0.17.3)
       multipart-post (>= 1.2, < 3)
     faye-websocket (0.10.9)
       eventmachine (>= 0.12.0)
@@ -368,6 +368,8 @@ GEM
     selenium-webdriver (3.142.7)
       childprocess (>= 0.5, < 4.0)
       rubyzip (>= 1.2.2)
+    sentry-raven (2.13.0)
+      faraday (>= 0.7.6, < 1.0)
     shoulda-matchers (4.2.0)
       activesupport (>= 4.2.0)
     simplecov (0.17.1)
@@ -499,6 +501,7 @@ DEPENDENCIES
   rubyzip
   sass-rails
   selenium-webdriver
+  sentry-raven
   shoulda-matchers
   simplecov
   slim-rails

config/initializers/raven.rb

@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+require 'concurrent'
+
+Rails.application.tap do |app|
+  pool = ::Concurrent::ThreadPoolExecutor.new(max_queue: 10)
+
+  Raven.configure do |config|
+    config.sanitize_fields = app.config.filter_parameters.map(&:to_s)
+
+    config.async = lambda do |event|
+      pool.post { ::Raven.send_event(event) }
+    end
+
+    # Do not sent full list of gems with each event
+    config.send_modules = false
+  end
+end