public IActionResult create(CourseCreateViewModels model)
 {
     if (ModelState.IsValid)
     {
         var course = new Course();
         course.Name     = model.Name;
         course.AuthorId = model.AuthorId;
         course          = _repositoryCourse.add(course);
         return(RedirectToAction(nameof(details), new { course.id }));
     }
     else
     {
         var course = new CourseCreateViewModels();
         course.authorsList = _repositoryCourse.SelectListItemAuthor();
         return(View(course));
     }
 }