return `self` on User#update_attributes
return `self` on User#update_attributes

fixes authentication

alphagov/trade-tariff-backend,bitzesty/trade-tariff-backend,alphagov/trade-tariff-backend,bitzesty/trade-tariff-backend,leftees/trade-tariff-backend,alphagov/trade-tariff-backend,leftees/trade-tariff-backend,leftees/trade-tariff-backend,bitzesty/trade-tariff-backend