handle db update

lib/Config/Activator.php

@@ -1,23 +1,20 @@
 <?php
 namespace MailPoet\Config;
-use \MailPoet\Config\Migrator;
-use \MailPoet\Config\Populator;
 
 if(!defined('ABSPATH')) exit;
 
 class Activator {
-  function __construct() {
-  }
-
-  function activate() {
+  static function activate() {
     $migrator = new Migrator();
     $migrator->up();
 
     $populator = new Populator();
     $populator->up();
+
+    update_option('mailpoet_db_version', Env::$version);
   }
 
-  function deactivate() {
+  static function deactivate() {
     $migrator = new Migrator();
     $migrator->down();
   }