Add version 0.1.0 of sysadmins: a way to add sudo users
Make sudo work like Ubuntu's defaults.

* Use a group called "admin"
* Require a password for sudo.

Requiring a password breaks Vagrant's provision and setup
and as such, we don't require a password in Vagrant.
Add the current changes to the changelog
Quoting according to houd-ci with double (") quotes
Make username the key of the list of sysadmins.
Change licence to MIT
Move sysadmins out of base role.

Don't run it by default, but make it a role.
Merge pull request #125 from berkes/feature/79-sudo-users

Feature #79 sudo users