Laravel Custom Authentication

LoginController.php

<?php

namespace App\Http\Controllers\Auth;

use App\Http\Controllers\Controller;
use Illuminate\Foundation\Auth\AuthenticatesUsers;
use Illuminate\Http\Request;
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 = '/home';

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

    public function login(Request $request)
    {
        $username = $request->username;

        $this->validate($request, [
            'username' => 'required', 'password' => 'required',
        ]);

        $field = filter_var($username, FILTER_VALIDATE_EMAIL) ? 'email' : 'username';

        $credentials = [$field => $username, 'password' => $request->password];

        if (Auth::attempt($credentials, $request->has('remember'))) {
            return $this->sendLoginResponse($request);
        }

        $this->incrementLoginAttempts($request);

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

    protected function authenticated(Request $request, $user)
    {
        if ($user->hasRole('admin')) {
            return redirect('/admin');
        }

        return redirect('home');
    }
}