capistrano/capistrano ? reverse-engineered prompt

Build me a Ruby based deployment tool that lets me run commands like cap staging deploy and cap production deploy from my terminal.

It should connect to remote servers over SSH, handle different environments like staging and production, and let me define tasks for things like restarting services after code is deployed. I want a simple default deployment flow that can be customized with my own Ruby task files, plus support for grouping servers by role like app, worker, and web so tasks only run where they should.

Make it feel like a real command line tool, with install and setup commands, a task listing command, and a dry run mode so I can see what would happen without changing anything. Use the usual Ruby project structure, and include good documentation for how to set up a project and write custom deploy steps. If you need to check current docs or best practices while building it, look them up online.