Add discord to the readme
[![Language grade: Java](https://img.shields.io/lgtm/grade/java/g/MovingBlocks/Terasology.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/MovingBlocks/Terasology/context:java)
[![License(code)](https://img.shields.io/badge/license(code)-Apache%202.0-blue.svg)](http://www.apache.org/licenses/LICENSE-2.0)
[![License(art)](https://img.shields.io/badge/license(art)-CC%20BY%204.0-blue.svg)](http://creativecommons.org/licenses/by/4.0/)
-[![IRC Channel](https://img.shields.io/badge/irc-%23terasology-blue.svg "IRC Channel")](https://webchat.freenode.net/?channels=terasology)
+[![Discord](https://img.shields.io/discord/270264625419911192.svg?label=discord)](http://discord.gg/Terasology)
+[![IRC Channel](https://img.shields.io/badge/irc-%23terasology-blue.svg "IRC (Outdated)")](https://webchat.freenode.net/?channels=terasology)
Welcome!
