How do I force or redirect my next.js website to use https

I thought this would be a simple task, but I struggle to find a way to force my webpage to use https.The next.js webapp lives on the heroku servers and I've set up the SSL. Both https and http version works, but how to I force or redirect the website to use the https version.I've seen some solution using express, but nothing in my webapp are using express, is it required?Thanks.