class Rails::Engine

def isolate_namespace(mod)
  engine_name(generate_railtie_name(mod.name))
  routes.default_scope = { module: ActiveSupport::Inflector.underscore(mod.name) }
  self.isolated = true
  unless mod.respond_to?(:railtie_namespace)
    name, railtie = engine_name, self
    mod.singleton_class.instance_eval do
      define_method(:railtie_namespace) { railtie }
      unless mod.respond_to?(:table_name_prefix)
        define_method(:table_name_prefix) { "#{name}_" }
      end
      unless mod.respond_to?(:use_relative_model_naming?)
        class_eval "def use_relative_model_naming?; true; end", __FILE__, __LINE__
      end
      unless mod.respond_to?(:railtie_helpers_paths)
        define_method(:railtie_helpers_paths) { railtie.helpers_paths }
      end
      unless mod.respond_to?(:railtie_routes_url_helpers)
        define_method(:railtie_routes_url_helpers) { |include_path_helpers = true| railtie.routes.url_helpers(include_path_helpers) }
      end
    end
  end
end