public async Task <ActionResult <CourseDto> > CreateCourse(CourseAddDto course)
{
var entity = _mapper.Map <Course>(course);
_courseRepository.AddCourse(entity);
await _courseRepository.SaveAsync();
var returnDto = _mapper.Map <CourseDto>(entity);
return(CreatedAtRoute(nameof(GetCourse), new { courseId = returnDto.Id }, returnDto));
}