Added config.dependency_loading.

config/environments/production.rb

@@ -64,4 +64,7 @@ Zammad::Application.configure do
   # Log the query plan for queries taking more than this (works
   # with SQLite, MySQL, and PostgreSQL)
   # config.active_record.auto_explain_threshold_in_seconds = 0.5
+
+  # autoload on
+  config.dependency_loading = true
 end