private async Task StoreAsync(UserAnswer answer)
 {
     try
     {
         this.db.UserAnswers.Add(answer);
         await this.db.SaveChangesAsync();
     }
     catch (Exception) { }
 }
        public async Task<IHttpActionResult> Post(UserAnswer answer)
        {
            if (!ModelState.IsValid)
            {
                return this.BadRequest(this.ModelState);
            }
            answer.LastModifiedDate = DateTime.Now;
            answer.SurveyId = 1;
            answer.UserEmail = User.Identity.Name;
            answer.UserId = User.Identity.GetUserId();
            answer.UserSurveyId = 0;

            await this.StoreAsync(answer);

            SurveyQuestion nextQuestion = await this.NextQuestionAsync(answer.UserId, 1);
            if (nextQuestion == null)
            {
                return this.NotFound();
            }

            return this.Ok(nextQuestion);
        }