sysmocom_dhl/lib/sysmocom_dhl_hooks.rb

class SysmocomDhlHooks < Spree::ThemeSupport::HookListener
  # custom hooks go here
  insert_after :admin_tabs do
      "<%= tab(:dhls) %>"
  end

  # Add the DHL label download
  insert_after :admin_shipment_edit_buttons, 'admin/dhls/address_label'
end