This reverts commit e81a297.
Users can add a gittip username to their profile, which will cause their profile page and the gem pages for any gems they own to link to relevant pages on gittip. As well, some API changes were needed so gittip could integrate effectively. These include: 1) gems/:gem_name/owners.:format now includes the gittip_username when the relevant profile has opted in. 2) profiles/:username.:format now exists, and returns profile info.
Conflicts: app/models/pusher.rb db/schema.rb features/push.feature test/unit/pusher_test.rb
This adds the ability for a gem to reference, via dependency, another gem that rubygems.org is not tracking. This allows flexibility in dependency storage.