public JsonResult Post(int id, [FromBody] TopicViewModel vm)
        {
            try
            {
                if (ModelState.IsValid)
                {
                    var newTopic = Mapper.Map <Topic>(vm);
                    _themeRepository.AddTopic(id, newTopic);

                    if (_themeRepository.SaveAll())
                    {
                        Response.StatusCode = (int)HttpStatusCode.Created;
                        return(Json(Mapper.Map <TopicViewModel>(newTopic)));
                    }
                }
            }
            catch (Exception ex)
            {
                _logger.LogError(ex.Message);
                Response.StatusCode = (int)HttpStatusCode.BadRequest;
                return(Json(new { ex.Message }));
            }
            Response.StatusCode = (int)HttpStatusCode.BadRequest;
            return(Json(new { Message = "Validation Failed.", ModelState }));
        }