public async Task<bool> Update(VehicleModel item)
        {
            var model = await IdExist(item.Id);

            model.Name = item.Name;
            model.BrandId = await BrandExist(item.BrandId);
            model.TypeId = await TypeExist(item.TypeId);

            if (item.Year != null) model.Year = item.Year;

            _db.Entry(model).State = EntityState.Modified;
            try
            {
                await _db.SaveChangesAsync();
            }
            catch (DbUpdateConcurrencyException exception)
            {
                throw new DbUpdateConcurrencyException(exception.Message);
            }

            return true;
        }
        public async Task<VehicleModel> Add(VehicleModel item)
        {
            var model = new VehicleModel
            {
                Name = item.Name,
                BrandId = await BrandExist(item.BrandId),
                TypeId = await TypeExist(item.TypeId),
            };

            if (item.Year != null) model.Year = item.Year;

            model = _db.VehicleModels.Add(model);
            try
            {
                await _db.SaveChangesAsync();
                return model;
            }
            catch (DbUpdateConcurrencyException exception)
            {
                throw new DbUpdateConcurrencyException(exception.Message);
            }
        }