gistfile1.rb

#Rails 2.3 features
User.admins.first.try(:address).try(:reset)

#--------------------------------------------
render :partial => 'articles/article', :locals => { :article => @article }
#--->
render @article

#-------------------------------------------
default_scope :order => 'created_at DESC'
Article.with_exclusive_scope { find(:all) }

#-------------------------------------------

#http://ryandaigle.com/articles/2009/2/1/what-s-new-in-edge-rails-nested-attributes
#--------------------------------------------------------------------------
class Person < ActiveRecord::Base

  validates_presence_of :name

  has_many :children, :class_name => 'Person'
  accepts_nested_attributes_for :children
    # can also be used on has_one etc.. associations

end

#---------------------------------------------------------------------

# Add a new child to this person
@person.children_attributes = { 'new_1' => { :name => 'Son' } }
@person.children #=> [ <#Person: name: 'Son'> ]
@person.children.clear

# Add two new children to this person
@person.children_attributes =
  { 'new_1' => { :name => 'Son' }, 'new_2' => { :name => 'Daughter' } }
@person.save
@person.children #=> [ <#Person: name: 'Son'>, <#Person: name: 'Daughter'> ]

# Edit the son (assuming id == 1)
@person.children_attributes = { '1' => { :name => 'Lad' } }
@person.save
  #=> the son's name is now 'Lad'

# Edit the daughter (id == 2) and add a new offspring
@person.children_attributes =
  { '2' => { :name => 'Lassie' }, 'new_1' => { :name => 'Pat' } }
@person.save
  #=> the daughter's name is now 'Lassie' and there's a new offspring called 'Pat'

# Remove Pat (id = 3), we don't like him/her
@person.children_attributes = { '3' => { '_delete' => '1' } }
@person.save
  #=> Pat is now deleted

#------------------------------------------------

<% form_for @person do |person_form| %>

  <%= person_form.label :name %>
  <%= person_form.text_field :name %>

  <% person_form.fields_for :children do |child_form| %>

    <%= child_form.label :name %>
    <%= child_form.text_field :name %>

    <% unless child_form.object.new_record? %>
      <%= child_form.checkbox '_delete' %>
      <%= child_form.label '_delete', 'Remove' %>
    <% end %>

  <% end %>

  <%= submit_tag %>
<% end %>