app

# File railties/lib/rails/commands/server/server_command.rb, line 25
    def app
      @app ||= begin
        app = super
        if app.is_a?(Class)
          ActiveSupport::Deprecation.warn(            Using `Rails::Application` subclass to start the server is deprecated and will be removed in Rails 6.0.            Please change `run #{app}` to `run Rails.application` in config.ru..squish)
        end
        app.respond_to?(:to_app) ? app.to_app : app
      end
    end