Defined the Todo model in the app target.

App/Sources/Views/ContentView.swift

@@ -7,7 +7,7 @@ struct ContentView: View {
     private var modelContext
 
     @Query
-    private var items: [Item]
+    private var items: [Todo]
 
     var body: some View {
         NavigationSplitView {
@@ -43,7 +43,7 @@ struct ContentView: View {
 
     private func addItem() {
         withAnimation {
-            let newItem = Item(timestamp: Date())
+            let newItem = Todo(title: "New Todo", due: Date())
             modelContext.insert(newItem)
         }
     }
@@ -59,5 +59,5 @@ struct ContentView: View {
 
 #Preview {
     ContentView()
-        .modelContainer(for: Item.self, inMemory: true)
+        .modelContainer(for: Todo.self, inMemory: true)
 }