add readme

examples/renderjs/readme.md

+# RenderJS TodoMVC Example
+
+> RenderJS is great for developing complex applications from reusable gadgets.
+Apps are asynchronous and give fine grained control as they are run as a 
+single chain of promises with Vanilla JS in between. Together with jIO connecting 
+and syncing with a storage of your choice, RenderJS/jIO allow to build robust
+and progressive web apps quickly.
+
+> _[Renderjs - renderjs.nexedi.com](https://renderjs.nexedi.com/)_
+> _[jIO - jio.nexedi.com](https://jio.nexedi.com/)_
+
+# Learning RenderJS
+Both websites contain the API and examples on how to develop applications with
+RenderJS and jIO.
+
+Here are some links you may find helpful:
+
+* [Source Code RenderJS](https://lab.nexedi.com/nexedi/renderjs) ([Github Mirror](https://github.com/nexedi/renderjs))
+* [Source Code jIO](https://lab.nexedi.com/nexedi/jio) ([Github Mirror](https://github.com/nexedi/jio))
+* [Applications built with Renderjs/jIO](https://officejs.com)