Adventures in Ruby and Capistrano

My my current project has seen a revisit of an old role - automating the deployment of distributed systems. Owing to the vagaries of consultancy, I found myself the developer and maintainer of a Ruby-themed deployment environment designed by someone else. I was thrown in the deep end, which is ok - the water was warm, and the current, gentle.

The (non-Ruby) components:
GitLab - centralised git repository management.
Jenkins - schedules, catalogues, and organises builds, and test runs.
Puppet - setup infrastructure and install underlying software. I'm aware that Puppet is built using Ruby, but as a user, this is well-hidden.

The Ruby bits:
rvm - The Ruby Version Manager. Installs and maintains the Ruby environment.
gem - a packaged up Ruby library. Analogous to a lightweight rpm, or (more of a stretch) msi file.
geminabox - server and caching proxy for gems built, and used.
bundle - a tool for managing gems.
rake - make in Ruby, can use gems.
Capistrano - a set of tools to do stuff (mostly rake) on other machines (via ssh).