add a small section with links to the smart-wallets page

docs/build/apps/smart-wallets.mdx

@@ -57,6 +57,14 @@ A passkey-powered multi-signer abstract account contract example.
 - View the [code](https://github.com/kalepail/superpeach)
 - Watch the [demo](https://youtu.be/0Agiwso2OMc?si=CHD9U8s-YLyqbXUJ)
 
+### Ye Olde Guestbook 📖
+
+A passkey-powered internet guestbook from yesteryear with smart contract and frontend code.
+
+- Use the [app](https://ye-olde-guestbook.vercel.app)
+- View the [code](https://github.com/ElliotFriend/ye-olde-guestbook)
+- Read the [tutorial](./guestbook/README.mdx)
+
 ### Passkey Kit 📦
 
 A client-side SDK tool for managing and using passkeys.