Adds Unicorn for production

Pivotal Tracker story: https://www.pivotaltracker.com/story/show/66233080

Related stories:
https://github.com/g5search/g5-content-management-system/pull/291
https://github.com/G5/g5-layout-garden/pull/19
https://github.com/g5search/g5-theme-garden/pull/68
https://github.com/G5/g5-hub/pull/28
https://github.com/G5/g5-configurator/pull/25
https://github.com/g5search/g5-client-app-creator/pull/29
https://github.com/g5search/g5-sibling-deployer/pull/14
https://github.com/G5/g5-widget-garden/pull/201