This is part of workaround to fix issue with building right_link sandbox and platform specific gems with ruby 1.9 - We package all gems with `bundle install` and `bundle package`, then build our sandbox ruby, and use gem executable from it to "install" platform specific gems. But `bundle package` is run from right_link_package which is using ruby 1.8 this leads to packaging of [rconv and ruby-debug gems](https://github.com/rightscale/right_link/blob/master/Gemfile#L53-L54) which are incompatible with ruby 1.9 so building of sandbox package fails. So we [changed build logic](https://github.com/rightscale/right_link_package/pull/127/files#diff-a98528131b4cca49843ce4bd6032f447R95) to not bundle any development gems at all, but rake gem is required on [building](https://github.com/rightscale/right_link_package/blob/master/lib/right_link_package/packaging/logic.rb#L102) rightlink package so we decided to move it out from :development group. Probably it would be better to update our build servers to use ruby 1.9 instead of 1.8