getting error while declaring wildcard into sleeping owl admin panel for laravel

I have added this menu into menu.php

Admin::menu()->url('user')->label('Users')->icon('fa-users')->uses('\SleepingOwl\Admin\Controllers\UsersController@index');

And its working ok, Now i want single user listing, So for that i want URL like this admin/user/{id}. What i tried is

Admin::menu()->url('user/{id}')->hidden()->uses('\SleepingOwl\Admin\Controllers\UsersController@getuser');

Not working,If i remove wildcard then it will work.

via Chebli Mohamed