post_install() {
  _ver=$(echo "$1" | sed -e "s:\([0-9]*\).*:\1:g")

  getent group redis >/dev/null || groupadd --system redis
  getent passwd redis >/dev/null || useradd --system -g redis \
    -d /var/lib/redis -s /bin/false redis

  install -dm700 var/lib/redis${_ver}
  chown redis:redis var/lib/redis${_ver}
}