title: Laravel $user->notifications return null
body: <p>I'm trying to get the notifications for a user. But when i the method get() in my NotificationController start it's always return null. This this the actual code i'm using to debug this feature :</p>
  
  <pre><code> function get(){
  
      $user = \App\User::find(12);
  
      dd($user-&gt;notifications);
  
  }
  </code></pre>
  
  <p>The route is with POST method, i use Postman to test it. I always get error 500 with null content.
  Do you know why ?
  Thank's in advance</p>
  
  <p><strong>[EDIT]</strong>
  This is the result of dd($user) for the get() method with POST request : </p>
  
  <pre><code>{ 
  "id": 13, 
  "rang": 1, 
  "image": "https://www.drupal.org/files/profile_default.jpg", 
  "firstname": "Donald", 
  "lastname": "Torp", 
  "email": "ashlynn.mcclure@pacocha.com", 
  "created_at": null, 
  "updated_at": null 
  }
  </code></pre>
  
  <p>This is the content of my DB notifications table actually :</p>
  
  <pre><code>ID : e7f54269-a5ff-4109-9b8a-c2328fb6cf98   
  Type : App\Notifications\IdeaSelected   
  notifiable_type : App\Idea  
  notifiable_id : 13  
  data : {"idea":{"id":39,"name":"okeefe","description":"Sunt soluta et eum. Vitae sint adipisci et excepturi eos est exercitationem velit. Mollitia hic aut aperiam cum incidunt dolorem sed. Ut blanditiis eos temporibus hic illum quis.","image":"https:\/\/lorempixel.com\/400\/280\/?98265","user":13,"created_at":null,"updated_at":null}}     
  read_at :   
  created_at : 2018-04-14 00:57:37
  </code></pre>
  
  <p>Result for <code>return (dd($user-&gt;load('notifications')));</code> :</p>
  
  <pre><code>#relations: array:1 [
      "notifications" =&gt; DatabaseNotificationCollection {#549
        #items: []
      }
    ]  
  </code></pre>
  
  <p>Result if i change the notifiable_type from App\Idea to App\User : </p>
  
  <pre><code>[
      {
          "id": "e7f54269-a5ff-4109-9b8a-c2328fb6cf98",
          "type": "User::class",
          "notifiable_type": "App\\User",
          "notifiable_id": 13,
          "data": {
              "idea": {
                  "id": 39,
                  "name": "okeefe",
                  "description": "Sunt soluta et eum. Vitae sint adipisci et excepturi eos est exercitationem velit. Mollitia hic aut aperiam cum incidunt dolorem sed. Ut blanditiis eos temporibus hic illum quis.",
                  "image": "https://lorempixel.com/400/280/?98265",
                  "user": 13,
                  "created_at": null,
                  "updated_at": null
              }
          },
          "read_at": null,
          "created_at": "2018-04-14 00:57:37",
          "updated_at": "2018-04-14 00:57:37"
      }
  ]
  </code></pre>