docs: function updateAgent(id, group, source, status) {
      var groupId = groups.indexOf(group);
      if (groupId <= 0) {
          console.error("ERROR: group='" + group + "' was not found.");
          return;
      }
      var sourceId = sources.indexOf(source);
      if (sourceId <= 0) {
          console.error("ERROR: source='" + source + "' was not found.");
          return;
      }
      console.log("UPDATE `Agents` SET `status`='" + status + "', " +
                  "`agentGroup_id`='" + groupId + "', " +
                  "`agentSource_id`='" + sourceId + "' WHERE " +
                  "`id`='" + id + "';");
  }