public async Task <ServiceResult <int> > Create(ProductCreateOrUpdateRequestViewModel viewModel)
        {
            var model = new Product();

            MapViewModelToModel(viewModel, model);

            var validator        = new ProductCreateOrUpdateRequestViewModelValidator();
            var validationResult = await validator.ValidateAsync(model);

            if (!validationResult.IsValid)
            {
                return(ServiceResultFactory.Fail <int>(validationResult));
            }

            await _repository.AddAsync(model);

            var changes = await _repository.SaveChangesAsync();

            if (changes == 0)
            {
                return(ServiceResultFactory.Fail <int>("Insert fails"));
            }
            return(ServiceResultFactory.Success(model.Id));
        }