Add ECS script to composer.json and update testing.md. (#11)

Author: terabytesoftw

composer.json

@@ -42,6 +42,7 @@
     },
     "scripts": {
         "check-dependencies": "composer-require-checker",
+        "ecs": "ecs check",
         "phpstan": "phpstan",
         "test": "phpunit"
     },

docs/testing.md

@@ -10,6 +10,15 @@ To run the checker, execute the following command:
 composer run check-dependencies
 ```
 
+## Easy coding standard
+
+The code is checked with [Easy Coding Standard](https://github.com/easy-coding-standard/easy-coding-standard) and
+[PHP CS Fixer](https://github.com/PHP-CS-Fixer/PHP-CS-Fixer). To run it:
+
+```shell
+composer run ecs
+```
+
 ## Static analysis
 
 The code is statically analyzed with [Phpstan](https://phpstan.org/). To run static analysis: