public ActionResult Index()
 {
     InitializeViewBag("Collections");
     var model = new CollectionsModel();
     model.People = new List<CollectionsPersonModel>();
     model.People.Add(new CollectionsPersonModel
     {
         Name = "Annabelle",
         Children = new List<string> { "Arnie", "Anders", "Apple" }
     });
     model.People.Add(new CollectionsPersonModel
     {
         Name = "Bertie",
         Children = new List<string> { "Boutros-Boutros", "Brianna", "Barbie", "Bee-bop" }
     });
     model.People.Add(new CollectionsPersonModel
     {
         Name = "Charles",
         Children = new List<string> { "Cayenne", "Cleopatra" }
     });
     return View(model);
 }
 public ActionResult AddChild(CollectionsModel model, int index)
 {
     model.AddChild(index);
     return Json(model);
 }