Add Discord badge (#124)

README.md

@@ -1,4 +1,4 @@
-# Flipper Zero Firmware community repo
+# Flipper Zero Firmware community repo [![Discord](https://img.shields.io/discord/740930220399525928.svg?label=&logo=discord&logoColor=ffffff&color=7389D8&labelColor=6A7EC2)](http://flipperzero.one/discord)
 
 ![](https://github.com/Flipper-Zero/flipperzero-firmware-community/raw/master/wiki_static/firmware-wiki-header.gif)