API Routing Problems

[Dante2]

Ok, I'm using the Head First Rails book, which sadly, was written in 2009. So, the API has changed drastically. I am trying to manually configure a route to make the controller find my show page. The route the book tells me to type map.connect '/ads/:id', :controller=>'ads', :action=>'show' But this is obviously not working. How would I rewrite this line of code to make it properly conform to the new API?

Thanks in advance.