Rails Engine Tips

engine.rb

module Refinery
  module CustomFeature
    class Engine < Rails::Engine

      initializer "core.load_app_instance_data" do |app|
        app.class.configure do
          # Add migrations to the host application's path
          config.paths['db/migrate'] += Refinery::Templates::Engine.paths['db/migrate'].existent
        end
      end

      config.to_prepare do
        # Add a custom helper
        Refinery::Admin::PagesController.helper(Refinery::Admin::CustomHelper)
      end
    end
  end
end

For more information see: https://gist.github.com/e139fa787aa882c0aa9c