dealing with invalid live data in migration

db/migrate/20150115050936_add_address_instances_to_existing_enterprise_groups.rb

@@ -6,7 +6,14 @@ class AddAddressInstancesToExistingEnterpriseGroups < ActiveRecord::Migration
       next if g.address.present?
       address = Spree::Address.new(firstname: 'unused', lastname: 'unused', address1: 'undefined', city: 'undefined', zipcode: 'undefined', state: state, country: country, phone: 'undefined')
       g.address = address
-      g.save
+      # some groups are invalid, because of a missing description
+      g.save!(validate: false)
     end
   end
+
+  def self.down
+    # we can't know which addresses were already there and which weren't
+    # and we can't remove addresses as long as they are referenced and
+    # required by the model
+  end
 end