/**
  * treatArticleBeforePersist
  * Article treatments common to add or edit article
  * @param \Gore\BlogBundle\Entity\Article $article
  * @return \Gore\BlogBundle\Entity\Article
  */
 private function treatArticleBeforePersist(Article $article)
 {
     $em = $this->getDoctrine()->getManager();
     // Traitement des valeurs par défaut
     $mgr = $this->get('gore_blog.blog_manager');
     foreach ($article->getKeywords() as $keyword) {
         $checkResult = $mgr->checkIfKeywordExists($keyword, true);
         if ($checkResult instanceof Keyword) {
             // if the keywords DOES exist in database
             $article->removeKeyword($keyword);
             $article->addKeyword($checkResult);
         } else {
             $em->persist($keyword);
         }
         $keyword->setCategory(false);
     }
     return $article;
 }