Update README.md (#84)

Author: nivisi

README.md

@@ -20,4 +20,5 @@ This project serves as a template project for Flutter applications. You can gene
 - [Slack Channel](https://TODO)
 - [OpenAPI Specification](https://TODO)
 - [NStack](https://TODO)
-- [Figma Design](https://TODO)
+- [Figma Design](https://TODO)
+- [UI Manifesto](https://github.com/monstar-lab-oss/ui-manifesto)