Bolt\Provider\ThumbnailsServiceProvider::boot PHP Method

    public function boot(Application $app)
    {
        $app['dispatcher']->addListener(ControllerEvents::MOUNT, function (MountEvent $event) {
            $app = $event->getApp();
            $event->mount($app['controller.thumbnails.mount_prefix'], $app['controller.thumbnails']);
        });
    }