Update README.md

Author: Andrewsimsd

README.md

@@ -2,6 +2,7 @@
 
 [![Crates.io](https://img.shields.io/crates/v/puzzle_engine.svg)](https://crates.io/crates/puzzle_engine)
 [![Documentation](https://docs.rs/puzzle_engine/badge.svg)](https://docs.rs/puzzle_engine)
+[![Tests](https://github.com/Andrewsimsd/puzzle_engine/actions/badge.svg)](https://github.com/Andrewsimsd/puzzle_engine/actions)
 [![License](https://img.shields.io/crates/l/puzzle_engine)](LICENSE)
 [![GitHub](https://img.shields.io/badge/GitHub-Repository-181717?logo=github)](https://github.com/andrewsimsd/puzzle_engine)