public async Task <IActionResult> Filter(string regNum)
        {
            IQueryable <VehicleViewModel> model;

            if (string.IsNullOrWhiteSpace(regNum))
            {
                model = db.VehicleModel.Select(v => new VehicleViewModel
                {
                    Id          = v.Id,
                    VehicleType = v.Type,
                    ArrivalTime = v.ArrivalTime,
                    RegNum      = v.RegNum
                });
            }
            else
            {
                model = db.VehicleModel
                        .Where(v => v.RegNum.Contains(regNum))
                        .Select(v => new VehicleViewModel
                {
                    Id          = v.Id,
                    VehicleType = v.Type,
                    ArrivalTime = v.ArrivalTime,
                    RegNum      = v.RegNum
                });
            }
            var vCollection = new VehiclesCollectionViewModel();

            vCollection.Vehicles = await model.ToListAsync();

            vCollection.TotalSpaces       = PARKING_CAPACITY;
            vCollection.ParkingSpacesLeft = LeftParkingSpaces();

            return(View(nameof(Vehicles), vCollection));
        }
        // GET: Vehicles
        public async Task <IActionResult> Vehicles()
        {
            var vCollection = new VehiclesCollectionViewModel();
            var model       = await db.VehicleModel.Select(v => new VehicleViewModel
            {
                Id          = v.Id,
                VehicleType = v.Type,
                RegNum      = v.RegNum,
                ArrivalTime = v.ArrivalTime,
            }).ToListAsync();

            vCollection.ParkingSpacesLeft = LeftParkingSpaces();
            vCollection.Vehicles          = model;
            vCollection.TotalSpaces       = PARKING_CAPACITY;

            return(View(vCollection));
        }