Update DigitalOcean provisioner to use ubuntu 14.04
Update README
Bump ruby version to 2.1.2
Update references from 'precise' (12.04) to 'trusty' (14.04)

Conflicts:
	roles/prepare_site_sampleapp/tasks/main.yml
Always accept github host key
Bump ruby version to 2.1.3
Bump ruby version to 2.1.5
Merge remote-tracking branch 'upstream/master'

Conflicts:
	README.md
	vars/defaults.yml