Add codesandbox to README

Author: rcdexta

README.md

@@ -5,7 +5,9 @@ Pluggable components to add a trello-like kanban board to your application
 [![Build Status](https://travis-ci.org/rcdexta/react-trello.svg?branch=master)](https://travis-ci.org/rcdexta/react-trello)
 [![npm version](https://badge.fury.io/js/react-trello.svg)](https://badge.fury.io/js/react-trello)
 
-[Demo](https://rcdexta.github.io/react-trello/)
+[![Edit react-trello-example](https://codesandbox.io/static/img/play-codesandbox.svg)](https://codesandbox.io/s/1o3zj95m9j)
+
+[Storybook](https://rcdexta.github.io/react-trello/)
 
 ## Features