Add supported module badge to readme

Author: Dylan Wagstaff

README.md

@@ -2,6 +2,7 @@
 [![Build Status](https://travis-ci.org/silverstripe/silverstripe-blog.svg?branch=master)](https://travis-ci.org/silverstripe/silverstripe-blog)
 [![Scrutinizer Code Quality](https://scrutinizer-ci.com/g/silverstripe/silverstripe-blog/badges/quality-score.png?b=master)](https://scrutinizer-ci.com/g/silverstripe/silverstripe-blog/?branch=master)
 [![codecov.io](https://codecov.io/github/silverstripe/silverstripe-blog/coverage.svg?branch=master)](https://codecov.io/github/silverstripe/silverstripe-blog?branch=master)
+[![SilverStripe supported module](https://img.shields.io/badge/silverstripe-supported-0071C4.svg)](https://www.silverstripe.org/software/addons/silverstripe-commercially-supported-module-list/)
 
 ## Documentation