Install ubuntu 18.04/xwindows with vagrant

Vagrantfile

Vagrant.configure(2) do |config|
  # Ubuntu 15.10
  config.vm.box = "bento/ubuntu-18.04"

  config.vm.provider "virtualbox" do |vb|
    # Display the VirtualBox GUI when booting the machine
    vb.gui = true
  end

  # Install xfce and virtualbox additions
  config.vm.provision "shell", inline: "sudo apt-get update"
  config.vm.provision "shell", inline: "sudo apt-get install -y xfce4 virtualbox-guest-dkms virtualbox-guest-utils virtualbox-guest-x11"
  # Permit anyone to start the GUI
  config.vm.provision "shell", inline: "sudo sed -i 's/allowed_users=.*$/allowed_users=anybody/' /etc/X11/Xwrapper.config"
end