Add app/workers/concerns to autoload paths

config/application.rb

@@ -26,6 +26,9 @@ module Gitlab
                                      #{config.root}/app/models/members
                                      #{config.root}/app/models/project_services))
 
+    # EE specific paths.
+    config.eager_load_paths.push("#{config.root}/app/workers/concerns")
+
     # Only load the plugins named here, in the order given (default is alphabetical).
     # :all can be used as a placeholder for all plugins not explicitly named.
     # config.plugins = [ :exception_notification, :ssl_requirement, :all ]