Update readme.md

Author: andrerpena

readme.md

@@ -10,6 +10,7 @@ A simple yet powerful and extensible **React Markdown Editor** that aims to have
 
 - [Demo](http://andrerpena.me/react-mde/)
 - [CodeSandbox Demo JSX ](https://codesandbox.io/s/react-mde-latest-5i5ov?file=/src/index.js)
+- [CodeSandbox Demo JSX - Using ReactMarkdown instead of Showdown](https://codesandbox.io/s/react-mde-latest-forked-f9ti5?file=/src/index.js)
 - [CodeSandbox Demo TSX ](https://codesandbox.io/s/react-typescript-i3wju?file=/src/index.tsx)
 - [CodeSandbox Demo TSX - Customized toolbar](https://codesandbox.io/s/react-typescript-m7cbx?file=/src/index.tsx)
 - [CodeSandbox Demo TSX - Custom command](https://codesandbox.io/s/react-typescript-icqgv?file=/src/index.tsx)