public ActionResult Assign(AssignTrainerToTopicViewmodel model)
        {
            //get trainer
            var role  = (from r in _context.Roles where r.Name.Contains("Trainer") select r).FirstOrDefault();
            var users = _context.Users.Where(x => x.Roles.Select(y => y.RoleId).Contains(role.Id)).ToList();

            //get topic

            var topics = _context.Topics.ToList();

            if (ModelState.IsValid)
            {
                _context.AssignTrainerToTopics.Add(model.AssignTrainerToTopic);
                _context.SaveChanges();
                return(RedirectToAction("Index"));
            }

            var TrainerTopicVM = new AssignTrainerToTopicViewmodel()
            {
                Topics               = topics,
                Trainers             = users,
                AssignTrainerToTopic = new AssignTrainerToTopic()
            };

            return(View(TrainerTopicVM));
        }
        public ActionResult Edit()
        {
            //get trainer
            var role  = (from r in _context.Roles where r.Name.Contains("Trainer") select r).FirstOrDefault();
            var users = _context.Users.Where(x => x.Roles.Select(y => y.RoleId).Contains(role.Id)).ToList();

            //get topic

            var topics = _context.Topics.ToList();

            var TrainerTopicVM = new AssignTrainerToTopicViewmodel()
            {
                Topics               = topics,
                Trainers             = users,
                AssignTrainerToTopic = new AssignTrainerToTopic()
            };

            return(View(TrainerTopicVM));
        }