laravel 5 overriding postRegister() include needed

I'm overriding the postRegister() method to disable the auto login after registration. Stackoverflow told me to modify this line:

Auth::login($this->create($request->all()));

to:

$user = $this->registrar->create($request->all());

Now I get an error saying:

Undefined property: App\Http\Controllers\Auth\AuthController::$registrar

My includes:

use App\User;
use Validator;
use App\Http\Controllers\Controller;
use Illuminate\Foundation\Auth\ThrottlesLogins;
use Illuminate\Foundation\Auth\AuthenticatesAndRegistersUsers;
use Cookie;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Auth;
use Illuminate\Support\Facades\Lang;
use Registrar;

What did I need to include?

via Chebli Mohamed