Update CONTRIBUTING.md (#32)

Author: jackbayliss

CONTRIBUTING.md

@@ -0,0 +1,21 @@
+# Contributing
+
+Thank you for considering contributing!
+
+Before submitting a pull request, ensure all tests pass.
+
+The project uses:
+
+- **Pest** for unit and feature tests.
+- **PHPStan** for static analysis.
+- **Pint** for code styling.
+
+All three are automatically run on every pull request.
+
+You can run them locally (recommended) with:
+
+```bash
+vendor/bin/pest
+vendor/bin/phpstan analyse
+vendor/bin/pint
+```