Support referral params sent via postback webhook (Facebook)

[johngriffin]

Issue #518 added support for referral params when they are received through the messaging_referral webhook. However, if you have get started screen configured and the user has had no previous communication with your bot then the referral params will be sent to you along with the postback when the user clicks the "Get Started" button:

https://developers.facebook.com/docs/messenger-platform/referral-params

This issue is for pushing the postback referral param through to the message that botkit exposes.

[benbrown]

Thanks!

[yestouscool]

Hello @johngriffin , I am a little bit confuse on which event will be triggered when a new user click your m.me link and which one will be triggered when an old user clicks ?
Inside Botkit 0.7.0 that I am using, I have facebook_referral and facebook_postback event that I am handling.

And also there is this problem when a user shared an object with postback button to a new user. What happens is the Get Started Screen pops up and from there the chatbot does not reply with the action corresponding to the payload of that postback button clicked.