gistfile1.rb

def set_default
    if addressable.kind_of?(User)
      if default_shipping?
        addressable.addresses.default_shipping.without(self).each{|a| a.update_attribute(:default_shipping, false) }
      else
        default_shipping = true if addressable.addresses.default_shipping.empty?
      end
      
      if default_billing?
        addressable.addresses.default_billing.without(self).each{|a| a.update_attribute(:default_billing, false) }
      else
        default_billing = true if addressable.addresses.default_shipping.empty?
      end
      
    end
  end