method_missing

# File railties/lib/rails/paths.rb, line 6
      def method_missing(id, *args)
        match = id.to_s.match(/^(.*)=$/)
        full  = [@current, $1 || id].compact.join("/")

        ActiveSupport::Deprecation.warn 'Accessing paths using dot style as in `config.paths.app.controller` is deprecated. Please use ' <<
          '`config.paths["app/controller"]` style instead.'

        if match || args.any?
          @root[full] = Path.new(@root, full, *args)
        elsif path = @root[full]
          path
        else
          super
        end
      end