serialize mongoid documents to json with an id attribute

1-model.rb

class Foo
  include Mongoid::Document
  field :bar
end

foo = Foo.new(:bar => "baz")
foo.to_json # => { _id: "(some uuid)", bar: "baz" }

2-tojson.rb

module Mongoid
  module Document
    def as_json(options={})
      attrs = super(options)
      attrs["id"] = attrs["_id"]
      attrs
    end
  end
end

Thanks Derek, thats a simple fix but brilliant!