Update CONTRIBUTING.md

CONTRIBUTING.md

@@ -7,9 +7,17 @@ Please help build JaxMARL into the best possible tool for the MARL community.
 We actively welcome your contributions!
  - If adding an environment or algorithm, check with us that it is the right fit for the repo.
  - Fork the repo and create your branch from main.
- - Add tests, or show proof that the environment/algorithm works.
+ - Add tests, or show proof that the environment/algorithm works. The exact requirements are listed below.
  - Add a README explaining your environment/algorithm.
 
+**Environment Requirements**
+ - Unit tests (in `pytest` format) demonstrating correctness. If applicable, show correspondence to existing implementations. If transitions match, write a unit test to demonstrate this ([example](https://github.com/FLAIROx/JaxMARL/blob/be9fe46e52a736f8dd766acf98b4e0803f199dd2/tests/mpe/test_mpe.py)).
+ - Training results for IPPO and MAPPO over 20 seeds, with configuration files saved to `baselines`.
+
+**Algorithm Requirements**
+ - Performance results on at least 3 environments (e.g. SMAX, MABrax & Overcooked) with at least 20 seeds per result.
+ - If applicable, compare performance results to existing implementations to demonstrate correctness.
+
 ## Bug reports
 
 We use Github's issues to track bugs, just open a new issue! Great Bug Reports tend to have: