Install ruby-rack-contrib by entering the following commands in the terminal:
sudo apt update sudo apt install ruby-rack-contrib
Description:
contributed Rack Middleware and Utilities
This package includes a variety of add-on components for Rack, a Ruby web server interface. For a full list, see /usr/share/doc/ruby-rack-contrib/README.md*
Homepage: http://github.com/rack/rack-contrib/
Version: 1.3.0-3
Section: universe/ruby