updated to Rails 4.2

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.
@@ -28,6 +21,9 @@ module CodeOcean
     # 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')
   end