rails new Test

    cd Test

    rails g scaffold hunter
    sed -i s/#.*/"has_many :animals"/ app/models/hunter.rb
    rails g scaffold animal hunter:references type:string
    sed -i s/"attr_accessible :type"/"attr_accessible :type, :id, :created_at, :updated_at"/ app/models/animal.rb
    rails g scaffold dog

    rake db:migrate

    rails console

    hunter = Hunter.create
    dog = Dog.new
    dog.hunter = Hunter.first
    dog_attributes = dog.attributes.merge(type: 'Dog')
    hunter.animals.build(dog_attributes)

    hunter.animals.first.is_a? Dog
    hunter.animals.first.is_a? Animal