Laravel - How to login with first name and last name?

How can i make a login in Laravel with first name, last name and password?

I've made a register / login with php artisan make:auth. I've changed some lines of code in the user's migration, in RegisterController.php, in LoginController.php and in User.php.

The registration works. But I have a problem with the login: the username() method in LoginController.php sets the username to 'first_name'. But it should be something like 'id' or 'first_name'.'last_name', because the first_name isn't unique. How can i do that?

If two persons have the same first name, the login will fail!

(Laravel 5.5.26)

User's migration:

Schema::create('users', function (Blueprint $table) {
    $table->increments('id');
    $table->string('first_name');
    $table->string('last_name');
    $table->string('password');
    $table->boolean('admin')->default(0);
    $table->boolean('active')->default(0);
    $table->string('avatar')->default('default_avatar.jpg');
    $table->unique(array('first_name', 'last_name'));
    $table->rememberToken();
    $table->timestamps();
});

LoginController:

<?php

namespace App\Http\Controllers\Auth;

use App\Http\Controllers\Controller;
use Illuminate\Foundation\Auth\AuthenticatesUsers;
use Illuminate\Support\Facades\Auth;

class LoginController extends Controller
{
    /*
    |--------------------------------------------------------------------------
    | Login Controller
    |--------------------------------------------------------------------------
    |
    | This controller handles authenticating users for the application and
    | redirecting them to your home screen. The controller uses a trait
    | to conveniently provide its functionality to your applications.
    |
    */

    use AuthenticatesUsers;

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

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

    public function username()
    {
        return 'first_name';
    }

    public function login(\Illuminate\Http\Request $request) {
        $this->validateLogin($request);

        // If the class is using the ThrottlesLogins trait, we can automatically throttle
        // the login attempts for this application. We'll key this by the username and
        // the IP address of the client making these requests into this application.
        if ($this->hasTooManyLoginAttempts($request)) {
            $this->fireLockoutEvent($request);
            return $this->sendLockoutResponse($request);
        }

        // This section is the only change
        if ($this->guard()->validate($this->credentials($request))) {
            $user = $this->guard()->getLastAttempted();

            // Make sure the user is active
            if ($user->active && $this->attemptLogin($request)) {
                // Send the normal successful login response
                return $this->sendLoginResponse($request);
            } else {
                // Increment the failed login attempts and redirect back to the
                // login form with an error message.
                $this->incrementLoginAttempts($request);
                return redirect()
                    ->back()
                    ->withInput($request->only($this->username(), 'remember'))
                    ->withErrors(['active' => 'Ihr Konto ist nicht aktiviert.']);
            }
        }

        // If the login attempt was unsuccessful we will increment the number of attempts
        // to login and redirect the user back to the login form. Of course, when this
        // user surpasses their maximum number of attempts they will get locked out.
        $this->incrementLoginAttempts($request);

        return $this->sendFailedLoginResponse($request);
    }
}

Register Controller:

<?php

namespace App\Http\Controllers\Auth;

use App\User;
use App\Http\Controllers\Controller;
use Illuminate\Support\Facades\Validator;
use Illuminate\Foundation\Auth\RegistersUsers;
use Illuminate\Http\Request;
use Illuminate\Auth\Events\Registered;

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 = '/';

    /**
     * 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, [
            'first_name'  => 'required|string|max:20|unique_with:users,last_name',
            'last_name' => 'required|string|max:20',
            'password' => 'required|string|min:6|confirmed',
        ]);
    }

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

    public function register(Request $request)
    {
        $this->validator($request->all())->validate();
        event(new Registered($user = $this->create($request->all())));
        return $this->registered($request, $user)
            ?: redirect($this->redirectPath());
    }
}

User.php:

<?php

namespace App;

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

class User extends Authenticatable
{
    use Notifiable;

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

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

    public function goals(){
        return $this->hasMany('App\Goal');
    }
}

via Chebli Mohamed