public async Task <IActionResult> GetAchievementByCourseNum(string Num)
        {
            var avs = await _achievementService.GetAchievementsByCourseNum(Num);

            if (avs.Count == 0)
            {
                return(NotFound());
            }
            var res = _mapper.Map <List <AchievementDto> >(avs);

            return(Ok(res));
        }