example usage of paper_trail

paper_trail_assoc.rb

# Parent class
class bookshelf
 has_many :books
 has_paper_trail
end

# Child class
class book
 belongs_to :bookshelf
 has_paper_trail
end


shelf = Bookshelf.create

shelf.books.create :title => "tale of two cities"

shelf.books # [#<Book id:1 title:"tale of two cities"]

shelf.books.create :title => "catcher in the rye"

shelf.books # [#<Book id: 1 title:"tale of two cities">, #<Book id:2 title:"catcher in the rye">]

shelf.previous_version.books # [#<Book id:1 title:"tale of two cities"]

I envisage paper_trail being able to do this if you update the shelf before adding the second book.