[ResponseType(typeof(Product))]
    public IHttpActionResult Put(int id, [FromBody]Product product)
    {
        try
        {

            if (product == null)
            {
                return BadRequest("Product cannot be null");
            }
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }
            var oldProduct = db.Products.Find(id);
            if (oldProduct == null)
            {
                return BadRequest("No such product");
            }
            db.Products.Remove(oldProduct);
            db.Products.Add(product);
            return Ok();

        }
        catch (Exception ex)
        {

            return InternalServerError(ex);
        }
    }