public ActionResult Create(Lecture lecture)
        {
            if (ModelState.IsValid)
            {
                context.Lectures.Add(lecture);
                context.SaveChanges();
                return RedirectToAction("Index");
            }

            ViewBag.PossibleCourses = context.Courses;
            return View(lecture);
        }
 public ActionResult Edit(Lecture lecture)
 {
     if (ModelState.IsValid)
     {
         context.Entry(lecture).State = EntityState.Modified;
         context.SaveChanges();
         return RedirectToAction("Index");
     }
     ViewBag.PossibleCourses = context.Courses;
     return View(lecture);
 }