---
- hosts: "{{ vms }}"
  become: true
  vars_prompt:
    - name: vms
      prompt: "hosts to run playbook on"
      private: no
    - name: group_name
      prompt: "Name of group to add user to"
      private: no
    - name: user_name
      prompt: "Name of user to add to group"
      private: no
  tasks:
    - name: Add user to group
      user:
        name: "{{ user_name }}"
        groups: "{{ group_name }}"
        append: yes