A shard is what we call a crystal library, and this is the website that lists them all.
Deploying to Heroku
To experiment with this, you can post this to your own heroku site.
You can read about Deploying to Heroku or just follow these steps:
NAME=crystal-shards-demo heroku create $NAME --buildpack https://github.com/zamith/heroku-buildpack-crystal git push heroku master