// DELETE api/timeslots/2
 public HttpResponseMessage Delete(int id)
 {
     var timeSlot = new TimeSlot { TimeSlotId = id };
       _db.TimeSlots.Attach(timeSlot);
       var status = _db.TimeSlots.Remove(timeSlot);
       _db.SaveChanges();
       if (status != null) return new HttpResponseMessage(HttpStatusCode.OK);
       throw new HttpResponseException(HttpStatusCode.NotFound);
 }
 //POST api/timeslots
 public HttpResponseMessage Post([FromBody]TimeSlotModel values)
 {
     var timeSlot = new TimeSlot
       {
      Start = values.TimeSlotStartTime,
      Duration = values.TimeSlotDuration
       };
       var ts = _db.TimeSlots.Add(timeSlot);
       _db.SaveChanges();
       if(ts!=null)
       {
      var msg = new HttpResponseMessage(HttpStatusCode.Created);
      msg.Headers.Location = new Uri(Request.RequestUri + "/" + timeSlot.TimeSlotId.ToString());
      return msg;
       }
       else
       {
      var msg = new HttpResponseMessage(HttpStatusCode.BadRequest);
      return msg;
       }
 }