class BuitineKeramika < ActiveRecord::Base
  #set_table_name "buitine_keramika"
  has_many :radinio_tipas, :as => :tipas
end


class Radinys < ActiveRecord::Base
  #set_table_name "radinys":radinio_tipas, :class_name => "RadinioTipas"
  has_many :radinio_tipas, :class_name => "RadinioTipas"
  has_one :adresas
end


class RadinioTipas < ActiveRecord::Base
  #set_table_name "radinio_tipas"
  belongs_to :radinys
  belongs_to :tipas, :polymorphic => true
end

# migration
    create_table :radinio_tipas do |t|
      t.column "radinys_id", :integer
      t.column "tipas_id", :integer
      t.column "tipas _type", :string
    end

# bandau vykdyti sitoki koda:

    @keramika = BuitineKeramika.new()
    @radinys.radinio_tipas.create(:tipas => @keramika)