title: How do I force or redirect my next.js website to use https
body: <p>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.</p>