public async Task<IHttpActionResult> Putproduct(int productId, product product)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }

            if (productId != product.productId)
            {
                return BadRequest();
            }

            db.Entry(product).State = EntityState.Modified;

            try
            {
                await db.SaveChangesAsync();
            }
            catch (DbUpdateConcurrencyException)
            {
                if (!productExists(productId))
                {
                    return NotFound();
                }
                else
                {
                    throw;
                }
            }

            return StatusCode(HttpStatusCode.NoContent);
        }
        public async Task<IHttpActionResult> Postproduct(product product)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }

            db.product.Add(product);
            await db.SaveChangesAsync();

            return Created("api/products", product);
        }