public async Task<IHttpActionResult> Post(Supplier supplier)
        {
            supplier.ProductFamilies = null;

            Supplier addedSupplier = _db.Suppliers.Add(supplier);
            await _db.SaveChangesAsync();
            return StatusCode(HttpStatusCode.NoContent);
        }
        public HttpResponseMessage Post(Supplier supplier)
        {
            supplier.ProductFamilies = null;

            Supplier addedSupplier = _db.Suppliers.Add(supplier);
            _db.SaveChanges();
            return Request.CreateResponse(HttpStatusCode.Created, addedSupplier);
        }
        public async Task<IHttpActionResult> Post(Supplier supplier)
        {
            supplier.ProductFamilies = null;

            Supplier addedSupplier = _db.Suppliers.Add(supplier);
            await _db.SaveChangesAsync();

            return Created(addedSupplier);
        }