Add Accessible react-modal

Author: caprica-Six

README.md

@@ -290,6 +290,7 @@ A collection of awesome things regarding the React ecosystem.
 - [react-gtm-module](https://github.com/alinemorelli/react-gtm) - Google Tag Manager Module for React.
 - [react-device-detect](https://github.com/duskload/react-device-detect) - Detect device for React.
 - [react-colorful](https://github.com/omgovich/react-colorful) - A tiny (2,5 KB), dependency-free, fast and accessible color picker component.
+- [react-modal](https://github.com/reactjs/react-modal) - Accessible modal dialog component for React.
 
 ##### React for Command Line