Update old LDAP provider name on gitlab

update-ldap-provider.rb

puts Identity.unscoped.group(:provider).count

users = User.includes(:identities).all

duplicated_providers = %w(ldap ldapmain).sort
old_provider = 'ldap'
new_provider = 'ldapmain'

users.each do |u|
  next if u.identities.blank?

  if u.identities.length == 1
    id = u.identities.first
    id.update_columns(provider: new_provider) if id.provider == old_provider
  else
    next if u.identities.map(&:extern_uid).uniq.length != 1
    if u.identities.map(&:provider).sort == duplicated_providers
      u.identities.where(provider: old_provider).delete_all
    end
  end
end

puts Identity.unscoped.group(:provider).count