Ruby Listings

It could be a good idea to create Ruby listings to support some interesting Ruby-based toolkits.

The repository is a compendium of community knowledge on game design and development, written in Rust but covering multiple languages. Look for existing listings in the repo structure, likely under directories like 'listings' or 'resources'. Determine the format for adding a new Ruby-based toolkit entry, then propose a specific toolkit and its description.

索引モデルが issue の本文から書いたものです。