public function generateThankYouUrl(RouterInterface $router, RenderContext $context)
    {
        /* @var $nodeTranslation NodeTranslation */
        $nodeTranslation = $context['nodetranslation'];

        return $router->generate('_slug', array(
            'url' => $context['slug'],
            '_locale' => $nodeTranslation->getLang(),
            'thanks' => true,
        ));
    }