mongoid_test.rb

#!/usr/bin/env ruby
gem 'bson_ext', '1.0.4'
gem "mongoid", '2.0.0.beta.19'
require 'mongoid'
require 'fabrication'

Mongoid.configure do |config|
  name = "test"
  host = "localhost"
  config.master = Mongo::Connection.new.db(name)
end

class User
  include Mongoid::Document
  field :name
end

class Feed
  include Mongoid::Document
  embeds_many :posts
end

class Post;
  include Mongoid::Document
  embedded_in :feed, :inverse_of => :post
end

f = Feed.create name: 'test'
f.posts.create title: 'foo'


feed = Feed.last

p feed.name
p feed.posts.last.title