add github user keys to authorized_keys via cloud-init/userdata

add-users.sh

#!/usr/bin/env bash

set -o nounset
set -o errexit
set -o pipefail
IFS=$'\n\t'

main(){
  users=( "tphummel" "githubuser2" "githubuser3" )
  ssh_user="ssh_user"

  for i in "${users[@]}"
  do
    curl "https://github.com/${i}.keys" >> "/home/${ssh_user}/.ssh/authorized_keys"
  done
}

main