Code snipet

    /**
     * @Route("/article/delete/{id}", name="article_delete")
     * @param $id
     * @param Request $request
     * @return \Symfony\Component\HttpFoundation\Response
     */
    public function delete($id, Request $request)
    {
        $article = $this->getDoctrine()->getRepository(Article::class)->find($id);

        if($article === null){
            return $this->redirectToRoute("blog_index");
        }

        $currentUser = $this->getUser();

        if(!$currentUser->isAuthor($article) && !$currentUser->isAdmin())
        {
            return $this->redirectToRoute("blog_index");
        }

        $form = $this->createForm(ArticleType::class, $article);

        $form->handleRequest($request);

        if($form->isSubmitted() && $form->isValid())
        {
            $em = $this->getDoctrine()->getManager();
            $em->remove($article);
            $em->flush();

            return $this->redirectToRoute('blog_index');
        }

        return $this->render('article/delete.html.twig', array('article' => $article, 'form' => $form->createView()));
    }