private ExerciseViewModel MapExercise(Exercise model)
 {
     var sets = new List<SetViewModel>();
     foreach (var set in model.Sets)
     {
         sets.Add(MapSet(set));
     }
     var viewModel = new ExerciseViewModel
     {
         Id = model.Id,
         Comment = model.Comment,
         ExerciseType = model.ExerciseType,
         Sets = sets
     };
     return viewModel;
 }
 private Exercise MapExerciseViewModel(ExerciseViewModel model)
 {
     var sets = new List<Set>();
     foreach (var set in model.Sets)
     {
         sets.Add(MapSetViewModel(set));
     }
     var exercise = new Exercise
     {
         Id = model.Id,
         Comment = model.Comment,
         ExerciseType = model.ExerciseType,
         Sets = sets
     };
     return exercise;
 }