Clear session on logoff

src/MusicStore/Controllers/AccountController.cs

@@ -437,6 +437,9 @@ namespace MusicStore.Controllers
         [ValidateAntiForgeryToken]
         public async Task<ActionResult> LogOff()
         {
+            // clear all items from the cart
+            Context.Session.Clear();
+
             await SignInManager.SignOutAsync();
 
             // TODO: Currently SignInManager.SignOut does not sign out OpenIdc and does not have a way to pass in a specific