post_install() {
    # Create nightfall user/group if it doesn't already exist
    [[ $(getent passwd nightfall) ]] \
        || useradd -d / -s /usr/bin/nologin nightfall
    return 0
}

post_upgrade() {
    # Run the install function on upgrade
    post_install
}

pre_remove() {
    # Remove the nightfall user/group if it exists
    [[ $(getent passwd nightfall) ]] \
        && userdel nightfall
    return 0
}