new readme shield for apache 2

README.md

@@ -17,3 +17,4 @@ Opbeat API is currently licensed under the [Apache License, Version 2.0](http://
 [![Build Status](https://travis-ci.org/hivesolutions/opbeat_api.svg?branch=master)](https://travis-ci.org/hivesolutions/opbeat_api)
 [![Coverage Status](https://coveralls.io/repos/hivesolutions/opbeat_api/badge.svg?branch=master)](https://coveralls.io/r/hivesolutions/opbeat_api?branch=master)
 [![PyPi Status](https://img.shields.io/pypi/v/opbeat_api.svg)](https://pypi.python.org/pypi/opbeat_api)
+[![License](http://img.shields.io/badge/license-Apache%202.0-blue.svg)](http://www.apache.org/licenses/)