Fixed gitter link

docs/readme.md

@@ -3,7 +3,7 @@
 
 [![Build Status](https://travis-ci.org/jlowe64/moodle-logstore_xapi.svg?branch=master)](https://travis-ci.org/jlowe64/moodle-logstore_xapi)
 [![Moodle Plugin Directory](http://img.shields.io/badge/moodle-plugin-orange.svg)](https://moodle.org/plugins/view/logstore_xapi)
-[![Gitter](https://badges.gitter.im/Join Chat.svg)](https://gitter.im/LearningLocker/learninglocker?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
+[![Gitter](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/LearningLocker/learninglocker?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 
 - [Installation](installation.md)
 - [Report bugs, enhancements, and questions](../contributing.md#issue-templates)