public async Task <IActionResult> Index(string message, int?page)
        {
            var devices = _devicesRepository.GetAll();

            if (!User.IsInRole(Helper.Admin))
            {
                var userId     = Helper.GetUserId(this.User);
                var userGroups = _groupsRepository.GetUserGroups(userId);

                devices = devices.Where(d => userGroups.Any(g => g.Id == d.GroupId));
            }

            ViewBag.Message = message;
            ViewBag.Current = "Devices";

            int pageSize = 15;

            return(View(await devices.ToPagedListAsync(page ?? 1, pageSize)));
        }