• rails/railtie
• rails/engine/railties
• active_support/callbacks
• active_support/core_ext/module/delegation
• active_support/core_ext/object/try
• pathname
• rake
• rails/generators

• 模块 AbstractController
• 模块 ActionDispatch
• 模块 ActiveSupport
• 模块 Rails
• 类 Rails::Engine