title: Undefined relation on laravel 5
body: <p>I have tow tables:</p>
  
  <p><strong>users(id,nom,role_id(fk),...)
  roles(id,role)</strong></p>
  
  <p>in users modele i create: </p>
  
  <pre><code>    public function role()
  {
      return $this-&gt;belongsTo('App\Role','role_id');
  }
  public function hasRole($role)
  {
      $role = $this-&gt;role();
      if (!is_null($role)) {
          $role = $role-&gt;role;
      } 
      return ($user_role===$role) ? true : false ;
  }
  public function whatRole()
  {
      $user_role = $this-&gt;roles();
      if (!is_null($user_role)) {
          $user_role = $user_role-&gt;role;
          return $user_role;
      }else{
          return false;
      }
  }
  </code></pre>
  
  <p>and in role modal i create :</p>
  
  <pre><code>    public function user()
  {
      return $this-&gt;hasMany('App\User');
  }
  </code></pre>
  
  <p>but when i try to use it like this : <code>Auth::user()-&gt;hasRole('medecin')</code>
  i get this error:</p>
  
  <pre><code>ErrorException in User.php line 25: Undefined property: Illuminate\Database\Eloquent\Relations\BelongsTo::$role (View: C:\wamp\www\Medecin2016\resources\views\pages\role_form.blade.php)
  
  in User.php line 25
  at CompilerEngine-&gt;handleViewException(object(ErrorException), '1') in PhpEngine.php line 43
  at PhpEngine-&gt;evaluatePath('C:\wamp\www\Medecin2016\storage\framework\views/018276e247e24f69812c603a17c57319', array('__env' =&gt; object(Factory), 'app' =&gt; object(Application), 'errors' =&gt; object(ViewErrorBag))) in CompilerEngine.php line 57
  at CompilerEngine-&gt;get('C:\wamp\www\Medecin2016\resources\views/pages/role_form.blade.php', array('__env' =&gt; object(Factory), 'app' =&gt; object(Application), 'errors' =&gt; object(ViewErrorBag))) in View.php line 142
  at View-&gt;getContents() in View.php line 111
  at View-&gt;renderContents() in View.php line 80 
  .......................
  </code></pre>