docs: @Override
      public void run(Reader in, Writer out) throws RuleException {
          //log("Adding field [" + field + "]");
          try {
              AddDoc addDoc = AddDoc.read(in);
              addDoc.getFields().add(field);
              addDoc.write(out);
          } catch (JAXBException jaxbe) {
              throw new RuleException(jaxbe.getLinkedException());
          }
      }