public function load(ObjectManager $manager)
 {
     for ($i = 0; $i < 40; $i++) {
         $article = new Article();
         $article->setTitle('News' . $i);
         $article->setContent('This is default content');
         $article->setDatetime(new \DateTime('- ' . rand(1, 4) . ' day'));
         $commentA = new Comment();
         $commentA->setAuthor('Author');
         $commentA->setContent('Comment .... default');
         $manager->persist($commentA);
         $article->addComment($commentA);
         $commentB = new Comment();
         $commentB->setAuthor('Author' . $i);
         $commentB->setContent('Comment .... default');
         $manager->persist($commentB);
         $article->addComment($commentB);
         $manager->persist($article);
     }
     $manager->flush();
 }