protected function registerMarkdown()
    {
        $this->app->singleton('markdown', function (Container $app) {
            $environment = $app['markdown.environment'];
            $docParser = new DocParser($environment);
            $htmlRenderer = new HtmlRenderer($environment);

            return new Converter($docParser, $htmlRenderer);
        });

        $this->app->alias('markdown', Converter::class);
        $this->app->alias('markdown', ConverterInterface::class);
    }