/**
  * Display a listing of the resource.
  *
  * @param  Request $request
  *
  * @return Response
  */
 public function index(Request $request)
 {
     // varianta simpla
     $users = User::all()->map(function ($item, $key) {
         $item->links = ['addresses' => 'addresses'];
         return $item;
     });
     return response()->json(['users' => $users]);
     // varianta cu datatables
     return Datatables::of(User::select('*'))->addColumn('links', function ($user) {
         return ['addresses' => 'addresses'];
     })->make(true);
 }