GitLab

This can successfully load rails console and rails server. There are
many, many problems still. The idea is this won't change anything under
rails 2.3, it's all backwards compatible.

closes CNVS-4711

test plan: `touch RAILS3` in your Canvas Rails.root directory. The run
`bundle update` and verify that you get rails 3 installed. Run `bundle
exec rails c` to load console or `bundle exec rails s` to start a
webrick server. You can login, though the dashboard currently breaks.
Also jammit isn't working yet.

But more importantly, Rails 2.3 should still work same as ever. All
tests should pass, and a basic regression sanity check would be good too.

Change-Id: Idd6f35de88adde84cd2db3a650f44b71bd6e9684
Reviewed-on: https://gerrit.instructure.com/18453

Reviewed-by: Brian Palmer <brianp@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Clare Hetherington <clare@instructure.com>
Product-Review: Bracken Mosbacker <bracken@instructure.com>