Url Redirection in django

Question

I have an app created in django and deployed at KeshavBits heroku. And after deploying app I purchased a domain (https://keshavbits.in/) and managed to point it to https://keshavbits.herokuapp.com/

So now I have two domains to acccess my website

1. https://keshavbits.herokuapp.com/
2. https://keshavbits.in/

Both links shows the same website i.e hosted at heroku but the problem is when someone logs in at keshavbits-heroku then session is stored under its domain so when they visit keshavbits.in they have to log in again.

I have checked django documentation and other stuff as well about multiple session manager but it works only when website is like home.keshavbits.in and play.keshavbits.in

So I thought to redirect traffic to keshavbits.in when someone hits https://keshavbits.herokuapp.com/

But I don't have any idea to do that.

Kindly help me :)