Merge pull request #396 from defuse/coverage-badge

Add coverage badge

Author: defuse

README.md

@@ -2,6 +2,7 @@ php-encryption
 ===============
 
 [![Build Status](https://travis-ci.org/defuse/php-encryption.svg?branch=master)](https://travis-ci.org/defuse/php-encryption)
+[![codecov](https://codecov.io/gh/defuse/php-encryption/branch/master/graph/badge.svg)](https://codecov.io/gh/defuse/php-encryption)
 [![Latest Stable Version](https://poser.pugx.org/defuse/php-encryption/v/stable)](https://packagist.org/packages/defuse/php-encryption)
 [![Latest Unstable Version](https://poser.pugx.org/defuse/php-encryption/v/unstable)](https://packagist.org/packages/defuse/php-encryption)
 [![License](https://poser.pugx.org/defuse/php-encryption/license)](https://packagist.org/packages/defuse/php-encryption)