Remove the govuk-backup user from admin and deploy groups
Remove the govuk-backup user from admin and deploy groups

This sets the additional groups to be an empty array and purges
membership of all non-listed additional groups. This will leave the
govuk-backup user in a group called govuk-backup.

alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet