public async Task <IActionResult> Challenge(int entryId, int workoutId)
        {
            var user = await GetCurrentUserAsync();

            var dto = await _workoutService.GetWorkoutEntryAsync(entryId);

            if (dto == null || user == null)
            {
                return(View("/Error")); // Error
            }
            var model = _mapper.Map <NewChallengeViewModel>(dto);

            Tempdata[user.Id]           = model;
            model.ChallengeAbleUserDtos = await _challengeService.GetChallengeAbleUsersAsync(user.Id);

            return(View(model));
        }