Ruby is installed on all DreamHost servers. The default versions on different server types are listed below.
All Shared servers run version 2.5.1.
New VPS machines purchased after March 2020 running Debian Stretch run 2.7.0.
All Dedicated servers purchased after March 2020 run version 2.5.1.
Other types of servers
Other hosting plan types are running 1.9.3, but will soon be updated.
Ruby on Shared hosting
Due to the amount of memory Ruby on Rails may use, it's not recommended to run an app on Shared hosting. You will most likely be hit the Shared server's memory limits.