The easiest way I found to create a new app in a version of Rails previous to 4.0?
- Create your new app: 'rails new new_app'.
- Open the Gemfile from a recent project using 3.2.12
- Copy the text of the Gemfile.
- cd into your new_app folder.
- Open the new_app Gemfile in your text editor.
- Paste the text you just copied into that Gemfile. This also ensures that the dependencies are there for your previous version of Rails. The dependencies for 4.0 will not work.
- Remove any gems you know you will not be using in new_app that you may have added to the previous app.
- 'bundle install' and you've got yourself a previous version and you've still got 4.0 installed.