public async Task <ActionResult <IEnumerable <LectureWithCourseResource> > > GetAllLectures()
{
var lectures = await _lectureService.GetAllLecturesWithCourse().ToListAsync();
var lecturesResource = _mapper.Map <IEnumerable <Lecture>, IEnumerable <LectureWithCourseResource> >(lectures);
return(Ok(lecturesResource));
}