//unos nove pjesme
 public HttpResponseMessage Post(Mp3Files mp3File)
 {
     if (ModelState.IsValid)
     {
         db.Mp3Files.Add(mp3File);
         db.SaveChanges();
         int idPjesme = mp3File.IDPjesme;
         HttpResponseMessage response = Request.CreateResponse(HttpStatusCode.Created, mp3File);
         response.Headers.Location = new Uri(Url.Link("DefaultApi", new { id = mp3File.IDPjesme }));
         return response;
     }
     else
     {
         return Request.CreateErrorResponse(HttpStatusCode.BadRequest, ModelState);
     }
 }
 //ažuriranje pjesme
 public HttpResponseMessage Put(int id, Mp3Files mp3Files)
 {
     if (!ModelState.IsValid)
     {
         return Request.CreateErrorResponse(HttpStatusCode.BadRequest, ModelState);
     }
     if (id != mp3Files.IDPjesme)
     {
         return Request.CreateResponse(HttpStatusCode.BadRequest);
     }
     db.Entry(mp3Files).State = EntityState.Modified;
     try
     {
         db.SaveChanges();
     }
     catch (DbUpdateConcurrencyException ex)
     {
         return Request.CreateErrorResponse(HttpStatusCode.NotFound, ex);
     }
     return Request.CreateResponse(HttpStatusCode.OK);
 }