This feature is only supported in the Ultimate edition.
The following is only valid when Ruby Plugin is installed and enabled!
- Open the Project Structure dialog (e.g. Ctrl+Shift+Alt+S).
- In the Project Structure dialog, click the node Modules.
- In the Gems tab, click
, and from the popup menu, choose
New local...:

- In the Select Ruby Interpreter Path dialog box, click the desired Ruby executable.