Update chat badge to vector.im

README.md

@@ -6,7 +6,7 @@
 [![Code Health](https://landscape.io/github/ViDA-NYU/reprozip/master/landscape.png)](https://landscape.io/github/ViDA-NYU/reprozip/master)
 [![Documentation Status](https://readthedocs.org/projects/reprozip/badge/?version=latest)]
 (http://reprozip.readthedocs.io/en/latest/)
-[![Gitter](https://badges.gitter.im/ViDA-NYU/reprozip.svg)](https://gitter.im/ViDA-NYU/reprozip?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge)
+[![Matrix](https://googledrive.com/host/0B3ucPz7GSthBekhIN1hMckJnRkE/matrix.svg)](https://vector.im/beta/#/room/#reprozip:matrix.org)
 
 ReproZip
 ========