docs: function showMessage(userId, msg, attachmentFileId) {
      var userLogin = getUserLoginById(userId);
      var messageHtml = buildMessageHTML(msg.body, userLogin, new Date(), attachmentFileId, msg.id);
  
      $('#messages-list').append(messageHtml);
  
      // scroll to bottom
      var mydiv = $('#messages-list');
      mydiv.scrollTop(mydiv.prop('scrollHeight'));
  }