Refer to SoundCloud's Stack Overflow tag in the Readme, instead of the old Google Group

Author: razola

README.md

@@ -5,7 +5,7 @@ So you want to share your tracks in your iOS Application to SoundCloud? With thi
 Afraid of doing the journey alone? Don't be, there's a lot of places where you can find help:
 
 * The [SoundCloud API Documentation](http://developers.soundcloud.com/docs). You'll need this.
-* The [SoundCloud API Discussion Group](http://groups.google.com/group/soundcloudapi).
+* The [SoundCloud tag](http://stackoverflow.com/questions/tagged/soundcloud) on Stack Overflow.
 * If you're looking for additional documentation on this wrapper have a look at the [wiki](http://wiki.github.com/soundcloud/cocoa-api-wrapper/) where you'll find the documentation for [version 1](http://github.com/soundcloud/cocoa-api-wrapper/tree/v1.0).
 
 Please keep in mind that all of this is under heavy development, and things might change from time to time. Please update your frameworks often, and keep this space in mind.