public HttpResponseMessage PostMultiTrackerReadings(List<TrackerReadingModel> trackerReadingModels)
 {
     TrackerReadingRepository repo = new TrackerReadingRepository();
     var ok = repo.AddReadings(trackerReadingModels);
     if (ok)
     {
         return Request.CreateResponse(HttpStatusCode.OK);
     }
     else
     {
         return Request.CreateResponse(HttpStatusCode.BadRequest);
     }
     
 }