updated rails from 4.1.13 to 4.2.5. This is required for rails to make use of new features in postgres 9.5

@Ralf
TODO: migration /Users/groucho/Documents/HPI/workspace/Xikolo-CodeOcean/codeocean/db/migrate/20160204111716_add_user_to_code_harbor_link.rb
is broken. A reference is made to table users which does not exist.
Workaround: run rake db:schema:load before running db:migrate. Still this should be fixed.

config/application.rb

@@ -1,13 +1,6 @@
 require File.expand_path('../boot', __FILE__)
 
-# Pick the frameworks you want:
-require "active_model/railtie"
-require "active_record/railtie"
-require "action_controller/railtie"
-require "action_mailer/railtie"
-require "action_view/railtie"
-require "sprockets/railtie"
-# require "rails/test_unit/railtie"
+require 'rails/all'
 
 # Require the gems listed in Gemfile, including any gems
 # you've limited to :test, :development, or :production.
@@ -21,17 +14,22 @@ module CodeOcean
 
     # Set Time.zone default to the specified zone and make Active Record auto-convert to this zone.
     # Run "rake -D time" for a list of tasks for finding time zone names. Default is UTC.
-    config.time_zone = 'Berlin'
+    config.time_zone = 'UTC'
 
     # The default locale is :en and all translations from config/locales/*.rb,yml are auto loaded.
     # config.i18n.load_path += Dir[Rails.root.join('my', 'locales', '*.{rb,yml}').to_s]
     # config.i18n.default_locale = :de
     config.i18n.available_locales = [:de, :en]
 
+    # Do not swallow errors in after_commit/after_rollback callbacks.
+    config.active_record.raise_in_transactional_callbacks = true
+
     config.autoload_paths << Rails.root.join('lib')
     config.eager_load_paths << Rails.root.join('lib')
     config.assets.precompile += %w( markdown-buttons.png )
 
+    config.active_record.schema_format = :sql
+
     case (RUBY_ENGINE)
       when 'ruby'
         # ...
@@ -43,5 +41,3 @@ module CodeOcean
     end
   end
 end
-
-Rails.application.config.assets.precompile += %w( markdown-buttons.png )