def build_contact(contact = {})
      case contact
        when Contact then   contact.gateway = self
        when Hash then      contact = Contact.new(contact.merge({:gateway => self}))
      end
      contact
    end
def build_contact(contact = {})
      case contact
        when Contact then   contact.gateway = self
        when Hash then      contact = Contact.new(contact.merge({:gateway => self}))
      end
      contact
    end
Factory method for building new Contact objects associated with this gateway.