Merge pull request #2170 from DjordyKoert/cleanup-commands

cleanup phpunit related things

CONTRIBUTING.md

@@ -11,7 +11,7 @@ You MUST follow the [PSR-1](http://www.php-fig.org/psr/psr-1/) and
 should really read the recommendations. Can't wait? Use the [PHP-CS-Fixer
 tool](http://cs.sensiolabs.org/).
 
-You MUST run the test suite (run `composer update`, and then execute `vendor/bin/simple-phpunit`).
+You MUST run the test suite (run `composer update`, and then execute `composer run phpunit`).
 
 You MUST write (or update) unit tests.
 

composer.json

@@ -90,5 +90,11 @@
         "branch-alias": {
             "dev-master": "4.x-dev"
         }
+    },
+    "scripts-descriptions": {
+        "phpunit": "Run phpunit"
+    },
+    "scripts": {
+        "phpunit": "phpunit"
     }
 }