added badge for license

README.md

@@ -8,7 +8,7 @@ PublicLab.org
 [![Code Climate](https://codeclimate.com/github/publiclab/plots2/badges/gpa.svg)](https://codeclimate.com/github/publiclab/plots2)
 [![Coverage Status](https://coveralls.io/repos/github/publiclab/plots2/badge.svg?branch=HEAD)](https://coveralls.io/github/publiclab/plots2?branch=HEAD)
 [![View performance data on Skylight](https://badges.skylight.io/typical/GZDPChmcfm1Q.svg)](https://oss.skylight.io/app/applications/GZDPChmcfm1Q)
-[![Newcomers welcome](https://img.shields.io/badge/newcomers-welcome-pink.svg)](https://code.publiclab.org)
+[![Newcomers welcome](https://img.shields.io/badge/newcomers-welcome-pink.svg)](https://code.publiclab.org) [![GitHub license](https://img.shields.io/github/license/publiclab/plots2?logo=gpl)](https://github.com/publiclab/plots2/blob/master/LICENSE)
 
 The content management system for the Public Lab research community, the `plots2` web application is a combination of a group research blog of what we call "research notes" and a wiki. Read more about the [data model here](https://github.com/publiclab/plots2/blob/master/doc/DATA_MODEL.md).