Padrino nested forms example

In request to basex's email http://groups.google.com/group/padrino/msg/37c1af9679774af9 on how to use nested forms, here's an example using Padrino's admin.

It's a one-minute draft and requires more work. Perhaps someone from the Padrino team may help here since I don't really know which is the best way -and if it's supported- to add a space for an empty address by default or how to allow adding new addresses to an existing Person.

I've sorted that out by attaching a new Address instance before both, new and edit are run, e.g.:

get :new do @person = Person.new @person.addresses << Address.new render 'people/new' end

The problem then is, what do you do with the blank record that's created? ActiveRecord's :reject_if => :all_blank should work (as stated here http://api.rubyonrails.org/classes/ActiveRecord/NestedAttributes/ClassMethods.html) but either I'm not using it properly or it just doesn't work here.

Now, the approach I've taken to achieve that isn't the best and I know that. I'm sure there's a best way to do it and I'd love to see this example improved. :) Hope this is useful! :)