title: Laravel 5.2 implicit route model binding using uuid string as id
body: <p>I'm setting up a new laravel installation and have come to an issue with implicit route model binding when using a uuid as an id.</p>
  
  <p>My route:</p>
  
  <pre><code>Route:group(['prefix' =&gt; 'admin'], function(){
      Route:resource('users', 'Admin\UserController');
  });
  </code></pre>
  
  <p>The show method of Admin\UserController:</p>
  
  <pre><code>public function show(App\User $user) {
      dd($user);
  }
  </code></pre>
  
  <p>So when I hit the URL <code>my.app/admin/users/long-uuid-string-here</code> I would expect to see the user information but I get an empty User object.</p>
  
  <p>When I add the following to the RouteServiceProvider, it works as expected:</p>
  
  <p><code>$router-&gt;model('admin/users', \App\User::class);</code></p>
  
  <p>Is there something I am missing, does implicit model binding expect an integer? Is it because it is in a route group or something else?</p>
  
  <p><strong>Yes!</strong> the id exists in the database, and I am using laravel 5.2</p>