def save!(options={:validate => true})
      unless save(options)
        raise Riagent::InvalidDocumentError.new(self)
      end
      true
    end
def save!(options={:validate => true})
      unless save(options)
        raise Riagent::InvalidDocumentError.new(self)
      end
      true
    end
Attempts to validate and save the document just like +save+ but will raise a +Riagent::InvalidDocumentError+
 exception instead of returning +false+ if the doc is not valid.