public function indexAction(Application $app, Request $request)
 {
     $rootDir = $app->getRootDir();
     $packagesJson = $rootDir . '/web/packages.json';
     $mtime = null;
     if (file_exists($packagesJson)) {
         $mtime = new \DateTime('@' . filemtime($packagesJson));
     }
     return new Response($app->get('templating')->render('Default/index.html.twig', array('updatedAt' => $mtime)));
 }