fix badge

Author: garak

README.md

@@ -1,7 +1,7 @@
 Doctrine Postgres Types Bundle
 ==============================
 
-[![Build Status](https://travis-ci.org/garak/doctrine-postgres-types-bundle?branch=master)](https://travis-ci.org/garak/doctrine-postgres-types-bundle)
+[![Build Status](https://travis-ci.org/garak/doctrine-postgres-types-bundle.svg?branch=master)](https://travis-ci.org/garak/doctrine-postgres-types-bundle)
 
 This bundle is for using [Doctrine Postgres Types](https://github.com/opensoft/doctrine-postgres-types) with Symfony.