public async Task Vote(Question question, string userName, string vote)
        {
            var user = await _context.Users.SingleAsync(u => u.Name == userName);

            var questionVote = question.Votes.SingleOrDefault(v => v.UserId == user.Id);

            if (questionVote == null)
            {
                questionVote = new QuestionVote
                {
                    Id   = Guid.NewGuid(),
                    User = user,
                    Vote = vote
                };
            }

            question.Votes.Add(questionVote);
        }
        public async Task Vote(Question question, string userName, string vote)
        {
			var user = await _context.Users.SingleAsync(u => u.Name == userName);
			var questionVote = question.Votes.SingleOrDefault(v => v.UserId == user.Id);
			
			if (questionVote == null) 
			{
				questionVote = new QuestionVote 
				{
					Id = Guid.NewGuid(),
					User = user,
					Vote = vote					
				};
			}
			
			question.Votes.Add(questionVote);
        }