Lae/app/Http/Controllers/Api/UserController.php

<?php

namespace App\Http\Controllers\Api;

use App\Http\Controllers\Controller;
use Illuminate\Http\Request;

class UserController extends Controller
{
    public function index(Request $request)
    {
        $user = $request->user()->load('user_group');

        return $this->success($user);
    }
}