public IActionResult DeleteSupermarket(int supermarketId)
        {
            // get supermarket for deleting
            var supermarketFromRepo = _supermarketRepository.GetSupermarketById(supermarketId);

            // check supermarket not null
            if (supermarketFromRepo == null)
            {
                return(NotFound());
            }

            // delete and save
            _supermarketRepository.DeleteSupermarket(supermarketFromRepo);

            if (!_supermarketRepository.Save())
            {
                throw new Exception($"Deleting supermarket {supermarketId} and associated stock failed on save.");
            }

            return(NoContent());
        }