Add Jenkins branch build script
Merge pull request #50 from alphagov/add_branch_builds

Add Jenkins branch build script
Test exposing bearer token issue
Add some missing dependencies to gemspec.

Also a missed require of omniauth.
Refactor bearer token to use warden-oauth2
Update bearer token fetch to include client_id

This fixes the token transfer issue (see
https://github.com/alphagov/signonotron2/pull/245 for more details)