public async Task <IActionResult> Post([FromBody] CreateCourseDto createCourseDto)
{
var lecturerId = createCourseDto.LecturerId;
var lecturer = await _lecturerRepo.FindAsync(lecturerId);
var course = await _coursesService.CreateAsync(createCourseDto.Name, lecturer, createCourseDto.Capacity);
return(Ok(course));
}