Rails 4.0 is finally released and probably you
want to migrate your apps to the latest version. So you change
the Rails version, execute
bundle and boom! You find that some
of your app's dependencies don't support Rails 4. Alright, now
you have a "situation".
Please help us by visiting the website and updating the status of a gem if you know that supports Rails 4 or not. We plan to add a feature to check if your app's Gemfile is ready to Rails 4.
You can contribute to the project on the GitHub repository.