Add Rarity to deployed examples

[morenoh149]

Rarity is a fully fledged implementation of standard d20-style game.

Checklist

• [.] The URL is not already present in the list (check with CTRL/CMD+F in the raw markdown file).
• [.] Each description starts with an uppercase character and ends with a period.
  Example: solc-js - JavaScript bindings for the compiler.
• [.] Drop all A / An prefixes at the start of the description.
• [ ] Avoid using the word Solidity in the description.