[Authorize(Roles = "admin")]
    public class AdminController : Controller
    {
        private readonly ILogger<AdminController> _logger;
        private readonly VoterCollectorContext _context;
            

        public AdminController(VoterCollectorContext context, ILogger<AdminController> logger)
        {
            _context = context;
            _logger = logger;
         }

        [HttpGet]
        public async Task<IActionResult> Index()
        {            
            List<Groupu> groupsUser =_serviceUser.GetGroupsUser(User.Identity.Name);
             Groupu mainGroup = _context.Groupu.Where(g => g.Name.Equals("Main")).FirstOrDefault();

           //...

        }

        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> Index([Bind("UserName", "Password", "ReturnUrl")] LoginModel loginViewModel)
        {
            List<Groupu> groupsUser = _serviceUser.GetGroupsUser(User.Identity.Name);
            Groupu mainGroup = _context.Groupu.Where(g => g.Name.Equals("Main")).FirstOrDefault();

          //...
        }