gistfile1.rb

require 'rubygems'
gem 'dm-core', '0.10.0'
require 'dm-core'

DataMapper.setup(:default, 'postgres://tpitale@localhost/test_through')
# DataObjects::Postgres.logger = DataObjects::Logger.new(STDOUT, :debug)

class Retailer
  include DataMapper::Resource

  property :id, Serial

  has n, :items, :through => Resource
end

class Item
  include DataMapper::Resource
  
  property :id, Serial
  
  has n, :retailers, :through => Resource
end

DataMapper.auto_migrate!

retailer = Retailer.create

10.times do
  retailer.items.new.save
end

# puts retailer.items

# retailer.reload
puts ItemRetailer.all == []
# puts retailer
# puts retailer.items

10.times do
  retailer.items.create
end

puts ItemRetailer.all == []