Ruby Language Support
To work with the Ruby programming language, you need to download and install the required ruby distribution: Download Ruby. IntelliJ IDEA automatically detects interpreters installed on a local machine and maintained by version managers. The following interpreters are supported:
Ruby MRI (version 1.8.7 and later)
Rubinius (without debugging)
For Rails projects, the following framework versions are supported:
Rails 3.2.x requires Ruby 1.8.7 or higher.
Rails 4 requires Ruby 1.9.x or higher.
Rails 5 requires Ruby 2.2.2 or higher.