Cache class in submodule

gistfile1.rb

# In genenal
# my_app/config/environments/development.rb
Rails.application.configure do
  # Settings specified here will take precedence over those in config/application.rb.

  # In the development environment your application's code is reloaded on
  # every request. This slows down response time but is perfect for development
  # since you don't have to restart the web server when you make code changes.
  config.cache_classes = false
end

# my_app/my_submodule/app/models/user.rb
require MyEngine::Engine.root.join('app', 'models', 'user')
class User
  # the code inside this class is cached, we must restart server to reload code
end