Add missing wiki pages and fix Plugin class constructor

includes/plugin.php

@@ -1 +1,54 @@
 <?php
+/**
+ * Main plugin class
+ *
+ * @package WPALLSTARS\PluginStarterTemplate
+ */
+
+namespace WPALLSTARS\PluginStarterTemplate;
+
+/**
+ * Plugin class
+ */
+class Plugin {
+
+    /**
+     * Core instance
+     *
+     * @var Core
+     */
+    private $core;
+
+    /**
+     * Plugin file
+     *
+     * @var string
+     */
+    private $plugin_file;
+
+    /**
+     * Plugin version
+     *
+     * @var string
+     */
+    private $version;
+
+    /**
+     * Constructor
+     *
+     * @param string $plugin_file Main plugin file path.
+     * @param string $version Plugin version.
+     */
+    public function __construct($plugin_file, $version) {
+        $this->plugin_file = $plugin_file;
+        $this->version = $version;
+        $this->core = new Core();
+    }
+
+    /**
+     * Initialize the plugin
+     */
+    public function init() {
+        // Initialize plugin
+    }
+}