For your Phoenix app - how did you configure nonwww and www domains in your DNS?

Here’s what my DNS settings look like at the moment on Namecheap.

And in my endpoint I’m only listening to the www domain and that www domain works. But when I visit the nonwww I want to redirect to the www endpoint.

config :my_app, MyAppWeb.Endpoint,  
  url: [host: "www.myapp.com", port: 80],

Render has pretty clear instructions on how to do this and it works fine.

Does anyone have tips for Fly.io? Thank you