Use shell provisioner to handle ubuntu packages, RVM and Ruby installation.
Use new custom base box URL.
Commented out shell provisioning that is already part of new base box.
PostgreSQL no longer used by checkpoint. Keep recipe, other pebbles may still need it.
Updated readme for custom base box.
Updated Berksfile.lock.
Commented out rake task db:schema:load, since it should only be run on empty databases.
AID-199 Changed api path back to /api/checkpoint since Varnish expects it.
Added recipe for generating custom config/site.rb for pebbles.
Merge branch 'custom_base_box'