How to route /app/name to /name?

map.connect ":name", :controller => "app"
where name is a GET parameter feed into the url on a link_to (or you
can type your domain_name/<whatever_name> to access the page
directly).

Ff I'm reading it correctly, you want to get to the action 'abc' with
a controller of 'app'?

map.connect "abc", :controller => "app", :action => "abc"

This only requires the controller and the action when you create a
link_to.
As for the url, "domain_name/abc" should work.