Merge pull request #1 from gitter-badger/gitter-badge

Add a Gitter chat badge to README.md

Author: matklad

README.md

@@ -1,5 +1,7 @@
 # libsyntax2.0
 
+[![Join the chat at https://gitter.im/libsyntax2/Lobby](https://badges.gitter.im/libsyntax2/Lobby.svg)](https://gitter.im/libsyntax2/Lobby?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
+
 libsyntax2.0 is an **experimental** implementation of the corresponding [RFC](https://github.com/rust-lang/rfcs/pull/2256).
 
 See `docs` folder for more details.