Overview
Ruby is installed on all DreamHost servers by default. You can confirm the version installed by logging into your server via SSH and running the following command:
[server]$ ruby -v
Ruby on Shared Hosting
Due to the amount of memory Ruby on Rails uses, running a Ruby app is only available on a VPS or Dedicated server.
Installing a current version of Ruby
VPS and Dedicated servers allow you to install any version you like using Ruby Version Manager.