Specify this act if you want to save a copy of the row in a versioned table. This assumes there is a versioned table ready and that your model has a version field. This works with optimisic locking if the lock_version column is present as well.

  class Page < ActiveRecord::Base
    # assumes pages_versions table
    acts_as_versioned
  end

Example:

  page = Page.create(:title => 'hello world!')
  page.version       # => 1

  page.title = 'hello world'
  page.save
  page.version       # => 2
  page.versions.size # => 2

  page.revert_to(1)  # using version number
  page.title         # => 'hello world!'

  page.revert_to(page.versions.last) # using versioned instance
  page.title         # => 'hello world'

See ActiveRecord::Acts::Versioned::ClassMethods#acts_as_versioned for configuration options