delete notification_user when user or notificaiton is deleted. Fixes...

delete notification_user when user or notificaiton is deleted. Fixes #997

src/Domain/Notification/Model/NotificationUser.php

@@ -53,14 +53,14 @@ class NotificationUser
     /**
      * @ORM\ManyToOne(targetEntity="App\Domain\Notification\Model\Notification", inversedBy="notificationUsers")
      *
-     * @ORM\JoinColumn(name="notification_id", referencedColumnName="id")
+     * @ORM\JoinColumn(name="notification_id", referencedColumnName="id", onDelete="CASCADE")
      */
     private Notification $notification;
 
     /**
      * @ORM\ManyToOne(targetEntity="App\Domain\User\Model\User", inversedBy="notifications")
      *
-     * @ORM\JoinColumn(name="user_id", referencedColumnName="id", nullable=true)
+     * @ORM\JoinColumn(name="user_id", referencedColumnName="id", nullable=true, onDelete="CASCADE")
      */
     private ?User $user;