private function createCartArticle(Cart $cart, Article $article, $quantity)
 {
     $cart_article = CartArticlePeer::getCartArticle($cart->getId(), $article->getId());
     if (isset($cart_article)) {
         $cart_article->setQuantity($cart_article->getQuantity() + $quantity);
         $cart_article->save();
         return $cart_article;
     }
     $cart_article = new CartArticle();
     $cart_article->setIdState(2);
     $cart_article->setCartId($cart->getId());
     $cart_article->setArticleId($article->getId());
     $cart_article->setDiscountId(1);
     //modificar yml
     $cart_article->setQuantity($quantity);
     $cart_article->setPrice($article->getPrice());
     //modificar price = price * discount
     $cart_article->save();
     return $cart_article;
 }