Rails 3 beta nested forms

Not sure if this the best place to look for rails 3.0 beta 3 help, but
I'll give it a try.

I can't seem to get nested forms to work in the beta - close but no
workie!

I used an approach similar to one I used in a 2.3 application to
update a user record from a profile record (citizen has_one :user,
accepts_nested_attributes_for :user ) except I'm try to create a user
record from a has_many relation (initial registration for a new group/
subdomain)

class Group < ActiveRecord::Base
  has_many :users
  accepts_nested_attributes_for :users, :allow_destroy => true
end

I have my nested form set up with:

    <%= f.fields_for :user, @user do |user_fields| %>
...

The form builds, but not the same has in 2.3

For instance, in 2.3 I'll get:

name="group[user_attributes][password_confirmation]"

in 3 I'll get:

name="group[user][password_confirmation]"

submitting the form will generate an error with unknown variable
"user"

Has anyone gotten nested forms to work in 3?
Am I missing some new approach that sets [group][user_attributes]
instead of [group] [user]?
Do you have to do something different with a nested has_many relation?
(since I assume it would normally be an array)

Steve Alex

It never fails! If you are having a problem trying to get something to
work, post something looking for help and within 15 minutes, you'll
figure it out!

I went back and reviewed the railscast on nested forms, which used a
has_many form and answered my 3rd question = you have to have an
array.

In my new action in the Groups controller I just added:

    1.times {@group.users.build}

and changed my fields_for to:

    <%= f.fields_for :users do |user_fields| %>

and everything worked! Singular - plural is something you just always
have to think of.

Steve