Check for no roles being attached #480 (#483)

app/Http/Controllers/Admin/UserController.php

@@ -243,10 +243,12 @@ class UserController extends Controller
         }
 
         // Delete all of the roles and then re-attach the valid ones
+        if (!empty($request->input('roles'))) {
             DB::table('role_user')->where('user_id', $id)->delete();
             foreach ($request->input('roles') as $key => $value) {
                 $user->attachRole($value);
             }
+        }
 
         Flash::success('User updated successfully.');