LaravelのMongodb操作パッケージjenssegers/mongodbを使って
Laravel同梱のAuthモジュールのデータベースをMongoDBに変えてみた。

ご参考程度で

環境情報

laradock
PHP7.2
Laravel 5.6
jenssegers/mongodb 3.4

App\User.php

<?php

namespace App;

use Illuminate\Notifications\Notifiable;
// ## ここが入れ替えの部分
//use Illuminate\Foundation\Auth\User as Authenticatable;
use Jenssegers\Mongodb\Auth\User as Authenticatable;

class User extends Authenticatable
{
    use Notifiable;

    /**
     * The attributes that are mass assignable.
     *
     * @var array
     */
    protected $fillable = [
        'name', 'email', 'password',
    ];

    /**
     * The attributes that should be hidden for arrays.
     *
     * @var array
     */
    protected $hidden = [
        'password', 'remember_token',
    ];
}