gistfile1.rb

class Addict
  include Mongoid::Document

  embeds_many :addict_photos
  accepts_nested_attributes_for :addict_photos

  field :date, :type => Date
end

gistfile2.txt

class AddictPhoto
  include Mongoid::Document

  embedded_in :addict, :inverse_of => :addict_photo
  mount_uploader :image, AddictUploader

  field :right, :type => Boolean
  field :left, :type => Boolean
  field :up, :type => Boolean
  field :down, :type => Boolean
  field :size, :type => Integer

end