title: eager loading return null on one to many relationship
body: <p>i have three table which have sort of many to many relationship
  the table name: notes(id,user_id,card_id,body), Users(id,name,password,...), Card(id,cardname,cardText)
  now i want to use eager loading to get the related user name
  i have three model which represented like here:</p>
  
  <pre><code>&lt;?php
  
  namespace App;
  
  use Illuminate\Database\Eloquent\Model;
  
  class Card extends Model
  {
      /*public $table= 'Fake';*/
      public $timestamps = false;
      public function notes()
      {
          return $this-&gt;hasMany(Note::class);
      }
  }
  
  &lt;?php
  
  namespace App;
  
  use Illuminate\Database\Eloquent\Model;
  
  class Note extends Model
  {
  
      public $timestamps = false;
      public function cards()
      {
          return $this-&gt;belongsTo(Card::class);
      }
  
      public function users()
      {
          return $this-&gt;belongsTo(User::class);
      }
  }
  
  &lt;?php
  
  namespace App;
  
  use Illuminate\Database\Eloquent\Model;
  
  class User extends Model
  {
      public $timestamps = false;
      public function notes()
      {
          return $this-&gt;hasMany(Note::class);
      }
  
  }
  </code></pre>
  
  <p>and in my route i used following:</p>
  
  <pre><code>&lt;?php
  
  use App\Card;
  Route::get('/', function () {
      $card=new Card();
      $card-&gt;id=1;
      $card-&gt;load('notes.users')-&gt;all();
      return $card;
  });
  </code></pre>
  
  <p>but i don't know why i get null in user in json:
  the json file:</p>
  
  <pre><code>{
  id: 1,
  notes: [
  {
  id: 1,
  card_id: 1,
  user_id: 1,
  body: "Hussein Jafari",
  users: null
  },
  {
  id: 2,
  card_id: 1,
  user_id: 1,
  body: "Ammpeaa",
  users: null
  },
  {
  id: 12,
  card_id: 1,
  user_id: 1,
  body: "KAIRIMI SANJABI",
  users: null
  },
  {
  id: 13,
  card_id: 1,
  user_id: 1,
  body: "MOAHAHS KASK KSK",
  users: null
  },
  {
  id: 14,
  card_id: 1,
  user_id: 1,
  body: "bENAJAJ KSAK KS",
  users: null
  }
  ]
  }
  </code></pre>