"uninitialized constant MongoMapper::Base" error when doing rake mongo:mongrate

I got the following error during my "rake mongo:mongrate" attempt:

$ rake mongo:mongrate --trace
(in /home/mei/Jobfully)
** Invoke mongo:mongrate (first_time)
** Invoke environment (first_time)
** Execute environment

** Execute mongo:mongrate
==  AddPricingPlans: migrating ================================================
-- add_column(:users, :plan_id, :string)
rake aborted!
uninitialized constant MongoMapper::Base
/home/mei/.rvm/gems/r开发者_如何学Cuby-1.9.2-p0/gems/activesupport-2.3.8/lib/active_support/dependencies.rb:440:in `rescue in load_missing_constant'

I have the following in my Gemfile -

gem 'rake', '~>0.8'
gem 'mongo',        '= 1.0.7'  # must be same version as bson/bson_ext
gem 'bson',         '= 1.0.4'  # must be same version as bson_ext/mongo
gem 'bson_ext',     '= 1.0.4'  # must be same version as bson/mongo
gem 'mongo_mapper', '~> 0.8.2'

I also added the following line in Rakefile -

import 'vendor/plugins/mongrations/lib/tasks/mongo.rake'

Any ideas on how I can fix this problem? Thanks.

MongoMapper::Base was deprecated sometime in the last year (it no longer even exists!). You now want MongoMapper.connection in lib/mongo_mapper/mongrations.rb, def connection rather than MongoMapper::Base.connection.

I'm not sure when it broke, but making that change has fixed mongrations for me.

If you want to monkeypatch it, you could use:

module MongoMapper
  class Base
    def self.connection
      MongoMapper.connection
    end
  end
end