Feature request: Appending query strings to domains

[wellhairy]

I'd like to be able to hook onto one or all domains specified in my config.yaml file and append a query string to a specified domain.

Something like:

domains:
  current:  "https://www.example.com"
  new:      
    url: "https://www.example.com"
    append: "?env=dev"

paths:
  home:     /
  contact:  /contact-us

With the output capturing urls as follows:

  current:  https://www.example.com/
            https://www.example.com/contact-us
            
  new:      https://www.example.com/?env=dev
            https://www.example.com/contact-us?env=dev

The documentation doesn't mention anything like this but is this something I could achieve now and if not is this a feature that might be developed in the future?

[npearce]

This would be AWESOME. Am working on a project where the only way to load the test theme is to pass a 'preview' parameter to prod. So the configuration would have to know to ONLY pass the param to one domain and not the other. Just as you have in your example above.

Please, please, please!

[kentr]

Would also be useful for busting caches, such as on sites behind a reverse proxy.