Merge pull request #180 from Yoast/composer_wp_plugin

Composer wp plugin

composer.json

@@ -1,6 +1,12 @@
 {
     "name": "yoast/duplicate-post",
     "description": "The go-to tool for cloning posts and pages, including the powerful Rewrite & Republish feature.",
+    "keywords": [
+        "wordpress",
+        "post",
+        "copy",
+        "clone"
+    ],
     "homepage": "https://wordpress.org/plugins/duplicate-post/",
     "license": "GPL-2.0-or-later",
     "authors": [
@@ -13,11 +19,12 @@
     "type": "wordpress-plugin",
     "support": {
         "issues": "https://github.com/Yoast/duplicate-post/issues",
-        "forum":  "https://wordpress.org/plugins/duplicate-post/",
+        "forum": "https://wordpress.org/support/plugin/duplicate-post",
         "source": "https://github.com/Yoast/duplicate-post"
     },
     "require": {
-        "php": ">=5.6"
+        "php": ">=5.6",
+        "composer/installers": "^1.9.0"
     },
     "require-dev": {
         "php-parallel-lint/php-parallel-lint": "^1.2",
@@ -53,6 +60,6 @@
         ]
     },
     "config": {
-      "classmap-authoritative": true
+        "classmap-authoritative": true
     }
 }