public IHttpActionResult PostRating(Rating rating)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }

            db.Ratings.Add(rating);

            try
            {
                db.SaveChanges();
            }
            catch (DbUpdateException)
            {
                if (RatingExists(rating.Id))
                {
                    return Conflict();
                }
                else
                {
                    throw;
                }
            }

            return CreatedAtRoute("DefaultApi", new { id = rating.Id }, rating);
        }
        public IHttpActionResult PutRating(int id, Rating rating)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }

            if (id != rating.Id)
            {
                return BadRequest();
            }

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

            try
            {
                db.SaveChanges();
            }
            catch (DbUpdateConcurrencyException)
            {
                if (!RatingExists(id))
                {
                    return NotFound();
                }
                else
                {
                    throw;
                }
            }

            return StatusCode(HttpStatusCode.NoContent);
        }