CHANGELOG: add description for patch 1514

Author: dannywillems

CHANGELOG.md

@@ -36,6 +36,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ([#1493](https://github.com/o1-labs/mina-rust/pull/1493))
 - **Website**: add search bar with Algolia
   ([#1493](https://github.com/o1-labs/mina-rust/pull/1509))
+- **Ledger/ZkAppCommand**: show how to build a ZkAppCommand from scratch, with
+  dummy values ([#1514](https://github.com/o1-labs/mina-rust/pull/1514))
 
 ### Changed