updated readme with project planning site

README.md

Feel free to contact us from our website at [http://www.revolvingcow.com](http://www.revolvingcow.com) or
our [Google+ page](https://plus.google.com/+Revolvingcow).
To report any issues or requests for new features check our project planning at
[https://trello.com/b/oEdKPYyW/grassfed](https://trello.com/b/oEdKPYyW/grassfed).