// POST api/Song
        public HttpResponseMessage PostSong(Song song)
        {
            if (ModelState.IsValid)
            {
                db.Songs.Add(song);
                db.SaveChanges();

                HttpResponseMessage response = Request.CreateResponse(HttpStatusCode.Created, song);
                response.Headers.Location = new Uri(Url.Link("DefaultApi", new { id = song.SongId }));
                return response;
            }
            else
            {
                return Request.CreateErrorResponse(HttpStatusCode.BadRequest, ModelState);
            }
        }
        // PUT api/Song/5
        public HttpResponseMessage PutSong(int id, Song song)
        {
            if (!ModelState.IsValid)
            {
                return Request.CreateErrorResponse(HttpStatusCode.BadRequest, ModelState);
            }

            if (id != song.SongId)
            {
                return Request.CreateResponse(HttpStatusCode.BadRequest);
            }

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

            try
            {
                db.SaveChanges();
            }
            catch (DbUpdateConcurrencyException ex)
            {
                return Request.CreateErrorResponse(HttpStatusCode.NotFound, ex);
            }

            return Request.CreateResponse(HttpStatusCode.OK);
        }