How to use the Browser Guard in Rails Discussion

If you're building a no build Rails application that makes use of modern browser features (like ONCE Campfire!), you'll definitely want to use this.

There is one trap to take care for: If your are using https://pagespeed.web.dev/ (Googles SEO tool) - you will get a -406 not acceptable - error. Looks like the pagespeed crawler is not recognized.