Oh My Zsh

We install Oh My Zsh (https://github.com/robbyrussell/oh-my-zsh) for the root user on the guest VM, because you know, it's useful!

We keep bash around for the Vagrant user, so if you'd prefer to use bash just remain as the vagrant user and sudo important commands, otherwise after ssh-ing onto the guest run sudo -i to become root, and get the Zsh goodness.