Chatwork│Slackへメッセージを転送する方法

var Chatwork_TOKEN ='xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx';//Chatwork APIトークン
var SLACK_TOKEN = 'xoxp-xxxxxxxxxxx-xxxxxxxxxxx-xxxxxxxxxxx-xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx';//Slack APIトークン
var MY_ID = 'xxxxxxx'; //自分のチャットワークID
var ROOM_ID = ["xxxxxxxx","xxxxxxxx","xxxxxxxx"];//取得したいチャットワークのルームID


function getChatwork(){
  var params = {
    headers : {"X-ChatworkToken" : Chatwork_TOKEN},
    method : "get"
  };
  for (var i = 0; i < ROOM_ID.length; i ++) {    
    var url = "https://api.Chatwork.com/v2/rooms/" + ROOM_ID[i] + "/messages?force=0";
    var strRespons = UrlFetchApp.fetch(url, params);
    if (strRespons != "") {      
      var json = JSON.parse(strRespons.getContentText());
      if(json == "") return;
    
      json.forEach(function(obj) {
        if(obj.body.indexOf(MY_ID) != -1){
          var message = '';
          for(var i in json){
            message = message + json[i].account.name + "\n```" + json[i].body + "```\n";
            postMessage(message);
          }
        }
      }); 
    }
  } 
}

function postMessage(message) {
  var url        = 'https://slack.com/api/chat.postMessage';
  var token      = SLACK_TOKEN;
  var channel    = "#general";
  var username   = "Chatwork"; 
  var parse      = 'full';
  var icon_emoji = ':robot_face:';
  var method     = 'post';
 
  var payload = {
      'token'      : token,
      'channel'    : channel,
      'text'       : message,
      'username'   : username,
      'parse'      : parse,
      'icon_emoji' : icon_emoji
  };
 
  var params = {
      'method' : method,
      'payload' : payload
  };
 
  var response = UrlFetchApp.fetch(url, params);
}