As described here, the proper way to open an existing Rails site in IDEA is:
- File -> New Project
- Create project from scratch (Next)
- For “Project files location” choose your Rails application directory, or a parent directory
- Leave “Create module” checked, select “Ruby Module” as the type”, and make sure the “content root” & “module file location” is set to the root of your Rails application (Next)
- Ensure your Ruby SDK is configured (Next)
- Ensure “Ruby on Rails” is checked, and fill out the appropriate settings under “Use existing Rails application” (Finish)
I have used this approach successfully in IntelliJ IDEA 11.0.2 and 11.1.3
If you don’t see Ruby as an option for the module type, ensure you have installed the Ruby plugin.