Add Discord server invitation link (#6405)

Author: Fly-Style

README.md

@@ -1,6 +1,7 @@
 # ChakraCore
 
 [![Join the chat at https://gitter.im/Microsoft/ChakraCore](https://badges.gitter.im/Microsoft/ChakraCore.svg)](https://gitter.im/Microsoft/ChakraCore?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
+[![Discord Chat](https://img.shields.io/discord/695166668967510077?label=Discord&logo=Discord)](https://discord.gg/3e49Ptz)
 [![Licensed under the MIT License](https://img.shields.io/badge/License-MIT-blue.svg)](https://github.com/Microsoft/ChakraCore/blob/master/LICENSE.txt)
 [![PR's Welcome](https://img.shields.io/badge/PRs%20-welcome-brightgreen.svg)](#contribute)