nested form for nested set

I wanted to create nested categories in the one form by using the nested model forms technique as described in Ryan's great Railscast http://railscasts.com/episodes/196-nested-model-form-part-1

Suppose I have a model category and it's using awesome_nested_set. When I go and create a new category I would like to have 3 sub categories built and I would like to create the main category and sub categories in one form.

Here is how I do that:

model

class Category < ActiveRecord::Base
  acts_as_nested_set
  accepts_nested_attributes_for :children
end

controller

class CategoriesController < InheritedResources::Base
  def new
    @category = Category.new
    3.times { @category.children.build(:name => "test") }
  end
end

My form

= form_for @category do |f|
  .field
    = f.label :name
    = f.text_field :name

  %p Sub categories
  - @category.children.each do |sub|
    = f.fields_for :children, sub do |child|
      = child.label :name
      = child.text_field :name
      %br

  .actions
    = f.submit 'Save'

You can further adapt this with jQuery to make it easy to add/remove new entries, this is covered by Ryan in his Railscast.

Firefox gotcha

http://stackoverflow.com/questions/6449323/using-awesome-nested-set-dynamically-adding-extra-children/6510808#6510808