How to change the Authentication model in Laravel

I need to change the default User model in my Laravel Application to Admin model. I followed the tutorial given in https://medium.com/@ZtuX/how-to-change-your-authentication-model-in-laravel-5-3-7a580a727d6f

the Admin model must do authentication, register and reset password. This is what I did so far.

After doing php artisan make:auth, I created Admin.php model

namespace Modules\Admin\Entities;

use Illuminate\Foundation\Auth\User as Authenticatable;
use Illuminate\Notifications\Notifiable;

class Admin extends Authenticatable
{
    use Notifiable;
    protected $fillable = ['name','email','password'];
    protected $hidden = [
        'password', 'remember_token',
    ];
}

This is config/auth.php

return [

    /*
    |--------------------------------------------------------------------------
    | Authentication Defaults
    |--------------------------------------------------------------------------
    |
    | This option controls the default authentication "guard" and password
    | reset options for your application. You may change these defaults
    | as required, but they're a perfect start for most applications.
    |
    */

    'defaults' => [
        'guard' => 'web',
        'passwords' => 'admins',
    ],

    /*
    |--------------------------------------------------------------------------
    | Authentication Guards
    |--------------------------------------------------------------------------
    |
    | Next, you may define every authentication guard for your application.
    | Of course, a great default configuration has been defined for you
    | here which uses session storage and the Eloquent user provider.
    |
    | All authentication drivers have a user provider. This defines how the
    | users are actually retrieved out of your database or other storage
    | mechanisms used by this application to persist your user's data.
    |
    | Supported: "session", "token"
    |
    */

    'guards' => [
        'web' => [
            'driver' => 'session',
            'provider' => 'admins',
        ],

        'api' => [
            'driver' => 'token',
            'provider' => 'users',
            'hash' => false,
        ],
    ],

    /*
    |--------------------------------------------------------------------------
    | User Providers
    |--------------------------------------------------------------------------
    |
    | All authentication drivers have a user provider. This defines how the
    | users are actually retrieved out of your database or other storage
    | mechanisms used by this application to persist your user's data.
    |
    | If you have multiple user tables or models you may configure multiple
    | sources which represent each model / table. These sources may then
    | be assigned to any extra authentication guards you have defined.
    |
    | Supported: "database", "eloquent"
    |
    */

    'providers' => [
        'users' => [
            'driver' => 'eloquent',
            'model' => \Modules\Admin\Entities\Admin::class,
        ],

        // 'users' => [
        //     'driver' => 'database',
        //     'table' => 'users',
        // ],
    ],

    /*
    |--------------------------------------------------------------------------
    | Resetting Passwords
    |--------------------------------------------------------------------------
    |
    | You may specify multiple password reset configurations if you have more
    | than one user table or model in the application and you want to have
    | separate password reset settings based on the specific user types.
    |
    | The expire time is the number of minutes that the reset token should be
    | considered valid. This security feature keeps tokens short-lived so
    | they have less time to be guessed. You may change this as needed.
    |
    */

    'passwords' => [
        'users' => [
            'provider' => 'admins',
            'table' => 'password_resets',
            'expire' => 60,
        ],
    ],

];

and this is RegisterController.php

namespace App\Http\Controllers\Auth;

use Modules\Admin\Entities\Admin;
use App\Http\Controllers\Controller;
use Illuminate\Support\Facades\Hash;
use Illuminate\Support\Facades\Validator;
use Illuminate\Foundation\Auth\RegistersUsers;

class RegisterController extends Controller
{
    /*
    |--------------------------------------------------------------------------
    | Register Controller
    |--------------------------------------------------------------------------
    |
    | This controller handles the registration of new users as well as their
    | validation and creation. By default this controller uses a trait to
    | provide this functionality without requiring any additional code.
    |
    */

    use RegistersUsers;

    /**
     * Where to redirect users after registration.
     *
     * @var string
     */
    protected $redirectTo = '/home';

    /**
     * Create a new controller instance.
     *
     * @return void
     */
    public function __construct()
    {
        $this->middleware('guest');
    }

    /**
     * Get a validator for an incoming registration request.
     *
     * @param  array  $data
     * @return \Illuminate\Contracts\Validation\Validator
     */
    protected function validator(array $data)
    {
        return Validator::make($data, [
            'name' => ['required', 'string', 'max:255'],
            'email' => ['required', 'string', 'email', 'max:255', 'unique:admins'],
            'password' => ['required', 'string', 'min:8', 'confirmed'],
        ]);
    }

    /**
     * Create a new user instance after a valid registration.
     *
     * @param  array  $data
     * @return \App\User
     */
    protected function create(array $data)
    {
        return Admin::create([
            'name' => $data['name'],
            'email' => $data['email'],
            'password' => Hash::make($data['password']),
        ]);
    }
}

This code creates a user in admins table, but when I try to login, it throws the following error

Argument 2 passed to Illuminate\Auth\SessionGuard::__construct() must be an instance of Illuminate\Contracts\Auth\UserProvider, null given, called in ...\vendor\laravel\framework\src\Illuminate\Auth\AuthManager.php on line 125

I can't understand why this error happens. Thanks for any help

via Chebli Mohamed