Flattr Button added to README

Author: ruflin

README.markdown

@@ -6,6 +6,7 @@ Elastica: elasticsearch PHP Client
 [![Coverage Status](https://coveralls.io/repos/ruflin/Elastica/badge.png)](https://coveralls.io/r/ruflin/Elastica)
 [![Dependency Status](https://www.versioneye.com/php/ruflin:Elastica/master/badge.png)](https://www.versioneye.com/php/ruflin:elastica/)
 [![Total Downloads](https://poser.pugx.org/ruflin/Elastica/downloads.png)](https://packagist.org/packages/ruflin/elastica)
+[![Flattr this git repo](http://api.flattr.com/button/flattr-badge-large.png)](https://flattr.com/submit/auto?user_id=ruflin&url=https://github.com/ruflin/Elastica&title=Elastica&language=PHP&tags=github&category=software)
 
 All documentation for Elastica can be found under [Elastica.io](http://Elastica.io/). If you have questions, don't hesitate to ask them in the [Elastica google group](https://groups.google.com/group/elastica-php-client). All library issues should go to the [issue tracker from github](https://github.com/ruflin/Elastica/issues).