Added Tree Tables to Readme (#414)

Co-authored-by: D070615 <[email protected]>

Author: etimr

README.md

@@ -90,7 +90,9 @@ User Interface related Features:
 - [Model Localization](https://cap.cloud.sap/docs/guides/i18n) for [English](app/_i18n/i18n.properties) and [German](app/_i18n/i18n_de.properties) language for static texts
 - [Custom File Upload extension](app/admin/webapp/extension/Upload.js) which provides a button for uploading `CSV` files
 - A simple Swagger UI for the CatalogService API at <http://localhost:8080/swagger/index.html>
-- UI5 Tree Table
+- UI5 [Tree Table](app/genres/webapp/manifest.json) with Value Help for [GenreHierarchy](app/admin/fiori-service.cds)
+- [Custom event handlers](https://cap.cloud.sap/docs/java/provisioning-api) for Tree Table such as the [Custom business logic for GenreHierarchy](srv/src/main/java/my/bookshop/handlers/HierarchyHandler.java).
+  Please note, that Tree Tables must be used with HANA. Custom event handler in this case provides a limited support ment for local testing.
 
 CDS Maven Plugin Features: