type: object
properties:
  user_ids:
    type: array
    items:
      type: integer
    description: IDs of users to add as channel members
  user_id:
    type: integer
    description: ID of a single user to add as a channel member
  role:
    type: string
    enum:
      - admin
      - member
    description: |
      Role to assign to the new members. Only account administrators can
      promote a new member to `admin` via this field; for any other caller
      the role is silently coerced to `member`.