public async Task AddLecture(int id, LectureCreatingBindingModel model)
        {
            var courseInstance = await this.DbContext.CourseInstances.FindAsync(id);

            var lecture = this.Mapper.Map <Lecture>(model);

            courseInstance.Lectures.Add(lecture);

            await this.DbContext.SaveChangesAsync();
        }
        public async Task <IActionResult> Add(int id)
        {
            if (!await this.courseInstancesService.InstamnceExists(instanceId: id))
            {
                return(NotFound());
            }

            var model = new LectureCreatingBindingModel()
            {
                CourseId = id
            };

            return(View(model));
        }
        public async Task <IActionResult> Add(int id, LectureCreatingBindingModel model)
        {
            await this.courseInstancesService.AddLecture(id, model);

            return(Redirect($"/Lecturer/CourseInstances/Details/{id}"));
        }