upgraded rails to 4.2 and dependencies. except rubocop

config/application.rb

@@ -37,6 +37,9 @@ module Osem
 
     # Configure the default encoding used in templates for Ruby 1.9.
     config.encoding = 'utf-8'
+    # Do not swallow errors in after_commit/after_rollback callbacks.
+    config.active_record.raise_in_transactional_callbacks = true
+
 
     # Configure sensitive parameters which will be filtered from the log file.
     config.filter_parameters += [:password]