Update README

Author: populov

README.md

@@ -73,8 +73,11 @@ Root of your rule builder.
 1. Create fork
 2. Checkout fork
 3. Develop locally as usual. **Code must follow [PSR-1](http://www.php-fig.org/psr/psr-1/), [PSR-2](http://www.php-fig.org/psr/psr-2/)**
-4. Update [README.md](README.md) to describe new or changed functionality. Add changes description to [CHANGES.md](CHANGES.md) file.
-5. When ready, create pull request
+4. Run [PHP_CodeSniffer](https://github.com/squizlabs/PHP_CodeSniffer) to ensure, that code follows style guides,
+and [PHPUnit](https://phpunit.de/) to ensure, that unit tests still pass.
+5. Add unit tests, that cover added or changed functionality.
+6. Update [README.md](README.md) to describe new or changed functionality. Add changes description to [CHANGES.md](CHANGES.md) file.
+7. When ready, create pull request
 
 ## Resources