snippet.rb

require 'active_record'
require 'logger'

puts "Active Record #{ActiveRecord::VERSION::STRING}"

ActiveRecord::Base.establish_connection(
  :adapter => 'postgresql',
  :database => 'test'
)

ActiveRecord::Schema.define do
  create_table :users, :force => true do |t|
    t.string :email
  end

  create_table :memberships, :force => true do |t|
    t.integer :user_id
  end
end

class User < ActiveRecord::Base
  has_many :memberships
end

class Membership < ActiveRecord::Base
end

ActiveRecord::Base.logger = Logger.new(STDOUT)

User.includes(:memberships).order('').where(:email => "rob@example.com").first