Deprecate rubyforge

I found this problem when I built ci-reporter today because:
* rubyforge is going to be [shutdown on May 15th](https://twitter.com/evanphx/status/399552820380053505). 
* it deprecated all rubyforge references in `hoe`. see [this commit](https://github.com/seattlerb/hoe/commit/6ff62f15b3629f2fb4029ad0d1d78d50028b36c5).