public function registerTwigEnvironment()
    {
        $this->app->singleton('twig', function ($app) {
            $twig = new \Twig_Environment(
                $app['twig.loader'],
                [
                    'auto_reload' => true,
                    'cache' => $app['config']['view.twig']
                ]
            );

            // Add Twig Debug Extension
            $twig->addExtension(new \Twig_Extension_Debug());

            // Enable debug.
            if ($app['config']['app.debug']) {
                $twig->enableDebug();
            }

            // Add WordPress helpers extension.
            $twig->addExtension(new WordPress());

            return $twig;
        });
    }