删除多对多关联symfony 3.4

namespace AppBundle\Entity;

use Doctrine\ORM\Mapping as ORM;

/**
 * @ORM\Entity
 * @ORM\Table(name="users")
 */
class User
{
    // ...
    
    /**
     * @ORM\ManyToMany(targetEntity="AppBundle\Entity\Group")
     * @ORM\JoinTable(name="user_groups",
     *     joinColumns={@ORM\JoinColumn(name="user_id", referencedColumnName="id")},
     *     inverseJoinColumns={@ORM\JoinColumn(name="group_id", referencedColumnName="id")}
     * )
     */
    private $groups;
    
    // ...
}

namespace AppBundle\Controller;

use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
use Symfony\Component\Routing\Annotation\Route;
use Doctrine\ORM\EntityManagerInterface;
use AppBundle\Entity\User;
use AppBundle\Entity\Group;

class UserController extends AbstractController
{
    /**
     * @Route("/user/{userId}/group/{groupId}/remove", name="remove_user_group")
     */
    public function removeUserGroup($userId, $groupId, EntityManagerInterface $entityManager)
    {
        $user = $entityManager->getRepository(User::class)->find($userId);
        $group = $entityManager->getRepository(Group::class)->find($groupId);
        
        if (!$user || !$group) {
            throw $this->createNotFoundException('User or Group not found.');
        }
        
        $user->removeGroup($group);
        $entityManager->flush();
        
        return $this->redirectToRoute('user_show', ['id' => $userId]);
    }
}

$ php bin/console doctrine:schema:update --force