Rails g schlägt bei mongoiden Befehlen fehl

Ich hatte verschiedene Bundler-/Gem-Probleme mit einem frischen Rails 3.2.3-Projekt, gefolgt von Ihrem Gemfile. Ich konnte es umgehen, indem ich Gemfile.lock entfernte und 'bundle install' erneut ausführte. Das Protokoll dessen, was ich getan habe, ist beigefügt und enthält das Herausschneiden von ActiveRecord. Hoffe, dass das hilft.

$ ruby -v
ruby 1.9.3p125 (2012-02-16 revision 34643) [x86_64-darwin11.3.0]
$ rails new free-11479-mongoid-rails-g
$ cd free-11479-mongoid-rails-g

Gemfile as per user

$ bundle install
You have requested:
  json ~> 1.6.3

The bundle currently has json locked at 1.7.1.
Try running `bundle update json`

$ bundle update json
Bundler could not find compatible versions for gem "multi_json":
  In Gemfile:
    rabl (~> 0.5.1) ruby depends on
      multi_json (~> 1.0.3) ruby

    guard-jasmine (>= 0) ruby depends on
      multi_json (1.3.4)

$ rm Gemfile.lock
$ bundle install
$ rails g mongoid:config
     create  config/mongoid.yml
---------
Assuming that you want to excise ActiveRecord...

dereference ActiveRecord

    config/application.rb
        #config.active_record.whitelist_attributes = true
    config/environments/development.rb
        #config.active_record.mass_assignment_sanitizer = :strict
        #config.active_record.auto_explain_threshold_in_seconds = 0.5
    config/environments/development.rb
        #config.active_record.mass_assignment_sanitizer = :strict
    test/test_helper.rb
      #fixtures :all

$ rm database.yml

config/application.rb
    #require 'rails/all'
    require "action_controller/railtie"
    require "action_mailer/railtie"
    require "active_resource/railtie"
    require "rails/test_unit/railtie"

$ rake test # passes