Adding/Update Related Data ASP.NET MVC 5 - asp.net-mvc

Question

I'm new to programming so I'm still learning.
I need to add Items to Grocery from a single view. But I can't get the data to save.
When I hit save I don't get any exceptions, the page just loads but nothing is saved to the
database. Can I get some help/guidance as to what I am doing wrong?
Data Class
public class Grocery
{
public int Id { get; set; }
public string Name { get; set; }
public virtual List<Item> Items { get; set; }
}
public class Item {
public int ItemId { get; set; }
public string Name { get; set; }
public string Description { get; set; }
}
View Model
public class GroceryViewModel
{
public Grocery Grocery { get; set; }
public virtual Item Item { get; set; }
public GroceryViewModel(int GroceryId)
{
using (var db = new MyContext())
{
Grocery = db.Groceries
.Include("Items")
.SingleOrDefault(a => a.Id == GroceryId);
}
}
}
Controller
public ActionResult Edit(int GroceryId, GroceryViewModel groceryViewModel)
{
var model = new GroceryViewModel(GroceryId);
var plusItems = new Item
{
Name = groceryViewModel.Item.Name,
Description = groceryViewModel.Item.Description,
};
db.Items.Add(plusItems);
db.SaveChanges();
return RedirectToAction(model);
View
#model Project.Models.GroceryViewModel
#using (Html.BeginForm()) {
#Html.AntiForgeryToken()
#Html.ValidationSummary(true)
<fieldset>
<legend>Groceries</legend>
<div class="editor-label">
#Html.LabelFor(model => model.Item.Name)
</div>
<div class="editor-field">
#Html.EditorFor(model => model.Item.Name)
#Html.ValidationMessageFor(model => model.Item.Name)
</div>
<div class="editor-label">
#Html.LabelFor(model => model.Item.Description)
</div>
<div class="editor-field">
#Html.EditorFor(model => model.Item.Description)
#Html.ValidationMessageFor(model => model.Description)
</div>
<p>
<input type="submit" value="Add Item" />
</p>
</fieldset>

Answer 1

try
using (var db = new MyContext())
{
var grocery = db.Groceries.Single(a => a.Id == groceryId);
var plusItems = new Item
{
Name = groceryViewModel.Item.Name,
Description = groceryViewModel.Item.Description,
};
grocery.Items.Add(plusItems);
db.SaveChanges();
}