为什么我的laravel auth没有被导入？

Question

我在Model函数中使用以下代码段。为什么它不承认Auth？这就是我的模型的样子。我正在关注本教程http://code.tutsplus.com/tutorials/build-web-apps-from-scratch-with-laravel-the-eloquent-orm--net-25631

use Illuminate\Auth\UserTrait;
use Illuminate\Auth\UserInterface;
use Illuminate\Auth\Reminders\RemindableTrait;
use Illuminate\Auth\Reminders\RemindableInterface;

类用户扩展了Eloquent    {

public static $timestamps = true;

protected $table = 'users';

public function user_profile()
{
    return $this->has_one('User_Profile');
}

public function photos()
{
    return $this->has_many('Photo');
}

public function viewed()
{
    return $this->has_many_and_belongs_to('User', 'interactions', 'viewer_id', 'viewee_id');
}

public function videos()
{
    return $this->has_many('Video');
}


}