Google script for creating auto header with date/time stamp in docs

code.gs

function onOpen() {
  // Add a menu with some items, some separators, and a sub-menu.
  DocumentApp.getUi().createMenu('Utilities')
      .addItem('New entry', 'insertDateStamp')
      .addToUi();
}

/**
 * Inserts the date at the current cursor location in boldface.
 */

function insertDateStamp() {
  var doc = DocumentApp.getActiveDocument();
  var body = doc.getBody();
  var user = Session.getActiveUser().getEmail()

  var date = Utilities.formatDate(new Date(), "GMT+2", "dd-MM-yyyy' @'HH:mm:ss"); // "yyyy-MM-dd'T'HH:mm:ss'Z'"
  body.appendPageBreak();
  var par = body.appendParagraph('<' + user + '> ' + date);
  //par.setBold(true);
  par.setHeading(DocumentApp.ParagraphHeading.HEADING3);
  body.appendHorizontalRule();
  var returnchar = body.appendParagraph("\r");
  var position = doc.newPosition(returnchar.getChild(0), 1);
  doc.setCursor(position);
}