title: problem to access authenticate user in register app service provider
body: <p>I have a problem to access Authenticate user in app service provider, here is my code. In cart Class (it's a custom class), I don't have access to current User.
  How can I access to Current user in custom Class?</p>
  <pre><code>public function register()
  {
     $this-&gt;app-&gt;singleton(Cart::class,function($app) {
         return new Cart($app-&gt;auth-&gt;user());
     });
  }
  </code></pre>