/// <summary>
/// Returns a collection of users who answered a question correctly.
/// </summary>
/// <param name="questionId"></param>
/// <returns></returns>
private async Task <IReadOnlyCollection <UserAnsweredQuestionCorrectlyViewModel> > GetUsersAnsweredCorrectlyAsync(int questionId)
{
var usersAnsweredCorrectly = await TriviaService.GetUsersAnsweredCorrectlyAsync(questionId);
return(Mapper.Map <IReadOnlyCollection <AnsweredQuestion>, IReadOnlyCollection <UserAnsweredQuestionCorrectlyViewModel> >(usersAnsweredCorrectly));
}