INFRA-8099: Adding gem installs of bundler and rake for all users

Note - I haven't tested this yet because I'm on an airplane and for some reason I can't ssh into the Y! boxes from this network. Weird.

Also, there's a remaining thing to add before this is done - dlang (http://downloads.dlang.org/releases/2014/dmd_2.066.0-0_amd64.deb) needs to be added to pkgrepo.apache.org, pkgrepo.apache.org needs to be added to sources.list, and dmd needs to be added to the list of packages to install. Opening an infra JIRA to get it added to the repo.