Allow sudo -g anyone and sudo -u anyone -g anytwo

When only the user (ALL) is specified explicitly, and the group is
implied, only sudo -u works. Specifying both the user and group, like
(ALL:ALL), is required to:

1. Use sudo -g by itself (with no -u user)
2. Use sudo -u and -g together, with a -g group that is different from
   the -u user's primary group

scripts/vagrant.sh

@@ -11,7 +11,7 @@ pw useradd -n vagrant -u 1001 -c 'Vagrant User' -d /home/vagrant \
 	-g 1001 -G 0 -m -M 0755 -w yes -s /usr/local/bin/bash
 
 # Configure sudo to allow the vagrant user
-echo 'vagrant ALL=(ALL) NOPASSWD: ALL' > /usr/local/etc/sudoers.d/vagrant
+echo 'vagrant ALL=(ALL:ALL) NOPASSWD: ALL' > /usr/local/etc/sudoers.d/vagrant
 chmod 0440 /usr/local/etc/sudoers.d/vagrant
 
 # Configure passwordless su to wheel users