public function showImage(\Twig_Environment $twig, User $user)
 {
     if ($user->getProfileImage()) {
         return $user->getProfileImage();
     } else {
         $gravatarApi = new GravatarApi();
         $gravatarHelper = new GravatarHelper($gravatarApi);
         if ($gravatarHelper->exists($user->getEmail())) {
             return $gravatarHelper->getUrl($user->getEmail());
         } else {
             return "/bundles/koalamonuser/images/no-profile-image.png";
         }
     }
 }