message: update syntax of getting started
diff: @@ -41,9 +41,9 @@ npm install --save botkit
  Then, add Botkit to your application code:
  ```javascript
  -var Botkit = require('botkit');
  +let { Botkit } = require('botkit');
  -var controller = new Botkit(MY_CONFIGURATION);
  +const controller = new Botkit(MY_CONFIGURATION);
  controller.hears('hello','direct_message', function(bot, message) {
  bot.reply(message,'Hello yourself!');
  