I'm given access to a Rails application which is hosted on a Linux machine. I need to setup a redirection from `www` to the root domain and, although it can be done via the application using `before_filter` or `route.rb`, it's better to do it via the web server. But I don't know what web server it's working on. It may or may not be nginx - I don't know. This is what I need to find out. How can I do that?