I am trying to use rails 4.0.0 with mongo_mapper 0.12.0 and getting that 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 is still not compatible?
Mongomapper 0.12.0 doesn't work with activesupport 4.0.0
You can check it on the file mongo_mapper.gemspec:
But you can use version 0.13.0.beta2, if you check the file mongo_mapper.gemspec for it:
So all you have to do in your Gemfile