Erorr Acl/Laravel in Laravel 5.1

Hello my friends to create user roles and permissions in the system that I have a problem with the implementation Laravel wanted to get help from your loved ones.

Package acl / laravel am and documentation that described the stage before I went to this part of the Get User Roles here when I write the following code UserController error in :

Documentation: http://ift.tt/1O3sQVF

Code shows: $ users = User :: all ();
         $ users -> getRoles ();
         return view ('users.index', compact ('users'));

Error :

BadMethodCallException in Macroable.php line 81:
Method getRoles does not exist.

I wanted to know exactly what's the problem Please advise.

Thanks

via Chebli Mohamed