Add a Bitdeli badge to README

Author: bitdeli-chef

README.md

@@ -107,4 +107,7 @@ You can also set your own response transformer which need to implement the `Resp
 **NOTE** At this moment only the "Database" resource has been implemented. The "Marketplace" and "User" are missing.
 
 ## Documentation
-Further documentation can be found at the [Discogs API v2.0 Documentation](http://www.discogs.com/developers/index.html).
+Further documentation can be found at the [Discogs API v2.0 Documentation](http://www.discogs.com/developers/index.html).
+
+[![Bitdeli Badge](https://d2weczhvl823v0.cloudfront.net/ricbra/php-discogs-api/trend.png)](https://bitdeli.com/free "Bitdeli Badge")
+