adds quality score

README.md

@@ -1,4 +1,4 @@
-Serializer
+Serializer [![Scrutinizer Quality Score](https://scrutinizer-ci.com/g/schmittjoh/serializer/badges/quality-score.png?s=189df68e00c75d3fe155bc0da0b53b53709a9895)](https://scrutinizer-ci.com/g/schmittjoh/serializer/)
 ==========
 
-Learn more about it in its [documentation](http://jmsyst.com/libs/serializer).
+Learn more about it in its [documentation](http://jmsyst.com/libs/serializer).