def writeable_attributes(*attrs)
      @writeable_attributes ||= []
      if attrs.any?
        @writeable_attributes.map!(&:to_sym).concat(attrs).uniq! if attrs.any?
        setup_attributes(@writeable_attributes, false)
      end
      @writeable_attributes
    end
def writeable_attributes(*attrs)
      @writeable_attributes ||= []
      if attrs.any?
        @writeable_attributes.map!(&:to_sym).concat(attrs).uniq! if attrs.any?
        setup_attributes(@writeable_attributes, false)
      end
      @writeable_attributes
    end
Writeable attributes are sent on POST/PUT.