private async Task SaveAchievement()
        {
            var model = AchievementRepository.GetAchievementAsync(_achievementId);

            model.Description      = Description;
            model.Title            = Title;
            model.GeneralTimeSpent = GeneralTimeSpent;
            model.AchievementSteps = AchievementSteps.ToAchievementStepViewModels();
            AchievementRepository.Save(model);
            if (_stepsToDelete.Any())
            {
                foreach (var stepViewModel in _stepsToDelete)
                {
                    var stepToDelete = AchievementStepRepository.GetAchievementStepAsync(stepViewModel.Id);
                    AchievementStepRepository.DeleteAchievementStep(stepToDelete);
                }
                _stepsToDelete.Clear();
            }
            if (GeneralTimeSpent >= 10000)
            {
                // TODO: make custom alert (at top of screen with animation)
                await UserDialogs.Instance.AlertAsync("Achieved");

                model.AchievedDate = DateTime.Now;
            }
            await NavigationService.NavigateBackAsync();
        }