feat: added phpunit + phpcodecoverage support

Author: sarahcssiqueira

.gitignore

@@ -1,4 +1,5 @@
 /db
 /themes
 /plugins
+/wp-core
 /vendor

composer.json

@@ -1,24 +1,26 @@
 {
   "name": "docker-wordpress/wordpress",
-  "description": "Docker WordPress Dev Environment, supports WP-CLI, phpMyAdmin, Xdebug",
-  "homepage": "https://github.com/sarahcssiqueira/docker-wordpress-with-wp-cli",
-  "license": "MIT",
-  "keywords": [
-    "wordpress",
-    "docker-environment"
-  ],
+  "description": "Docker WordPress Dev Environment, supports WP-CLI, phpMyAdmin, Xdebug, PHPCS",
+  "homepage": "https://github.com/sarahcssiqueira/docker-wordpress",
   "authors": [
     {
       "name": "sarahcssiqueira",
       "email": "[email protected]",
       "homepage": "https://sarahjobs.com/"
     }
   ],
+  "license": "MIT",
+  "keywords": [
+    "wordpress",
+    "docker-environment"
+  ],
   "type": "project",
   "require": {
     "php": ">=7.1.3"
   },
   "require-dev": {
+    "phpunit/phpunit": "^9.6",
+    "phpunit/php-code-coverage": "^9.2",
     "squizlabs/php_codesniffer": "^3.7",
     "wp-coding-standards/wpcs": "^2.3"
   }