Set mongodb as recommendation only
create new defaults for the unicorn.rb template
Remove unicorn & system ruby dependency, replace with rbenv
Replace init script for su-ing into rbenv user

Shamelessly stolen from GitLab
https://github.com/gitlabhq/gitlabhq/blob/master/lib/support/init.d/gitlab
Rename unicorn.conf -> unicorn.rb
Set environment in rbenv user's .bash_profile instead of global profile

Setting in the global profile is not necessary anymore
Don't restart errbit_unicorn unless config changed
Remove system ruby from Vagrantfile
Merge branch 'rbenv'

Conflicts:
	README.md