How to use mongo_mapper with rails 4?

Question

I am trying to use rails 4.0.0 with mongo_mapper 0.12.0 and receive this message

Bundler could not find compatible versions for gem "activesupport": In Gemfile: mongo_mapper (~> 0.12.0) ruby depends on activesupport (~> 3.0) ruby rails (= 4.0.0) ruby depends on activesupport (4.0.0) 

Rails 4 and mongo_mapper still not compatible?

Answer 1

Mongomapper 0.12.0 does not work with activesupport 4.0.0

You can check it in the mongo_mapper.gemspec file:

 s.add_dependency 'activemodel', '~> 3.0' 

But you can use version 0.13.0.beta2 if you check the mongo_mapper.gemspec file for it:

 s.add_dependency 'activesupport', '>= 3.0' 

So, all you have to do in your Gemfile

 gem 'mongo_mapper', '>= 0.13.0.beta2'