gistfile1.rb

class Icon
  include Mongoid::Document
  field :tiny, type: Hash
  field :small, type: Hash
  field :medium, type: Hash
  field :large, type: Hash
  has_many :categories
end

class Category
  include Mongoid::Document
  field :name, type: String
  field :title, type: String
  field :keywords, type: Array
  field :description, type: String
  belongs_to :icon
end


irb(main):001:0> Category.first.icon
=> nil
irb(main):002:0> Category.first.icon=Icon.first
=> #<Icon _id: 4de2c203f9b01648a1000027, _type: nil, tiny: {"x"=>192, "y"=>100, "width"=>12, "height"=>17}, small: {"x"=>192, "y"=>67, "width"=>23, "height"=>33}, medium: {"x"=>0, "y"=>67, "width"=>32, "height"=>47}, large: {"x"=>0, "y"=>0, "width"=>46, "height"=>65}>
irb(main):003:0> Category.first.icon
=> nil