Add info in the README about the invite part

README.md

@@ -4,6 +4,7 @@
 - Supposed to trigger a welcome message when someone joins the room, but instead it appears that [m.member](https://matrix-nio.readthedocs.io/en/latest/nio.html#nio.events.room_events.RoomMemberEvent) events are too generic.
 - Connects to WhatsApp using [mautrix/whatsapp](https://github.com/mautrix/whatsapp)
 - PRs welcome.
+- If you want to see how messages are sent, [here](https://github.com/hegdenischay/bangalore-welcome-bot/blob/master/bangalore_bot/callbacks.py#L83)
 
 
 # Nio Template [![Built with matrix-nio](https://img.shields.io/badge/built%20with-matrix--nio-brightgreen)](https://github.com/poljar/matrix-nio) <a href="https://matrix.to/#/#nio-template:matrix.org"><img src="https://img.shields.io/matrix/nio-template:matrix.org?color=blue&label=Join%20the%20Matrix%20Room&server_fqdn=matrix-client.matrix.org" /></a>