Add subscriber source

[MAILPOET-1377]

lib/Models/Subscriber.php

@@ -2,6 +2,7 @@
 namespace MailPoet\Models;
 use MailPoet\Mailer\Mailer;
 use MailPoet\Newsletter\Scheduler\Scheduler;
+use MailPoet\Subscribers\Source;
 use MailPoet\Util\Helpers;
 use MailPoet\Subscription;
 
@@ -182,6 +183,8 @@ class Subscriber extends Model {
       // create new subscriber or update if no confirmation is required
       $subscriber = self::createOrUpdate($subscriber_data);
       if($subscriber->getErrors() !== false) {
+        $subscriber = Source::setSource($subscriber, Source::FORM);
+        $subscriber->save();
         return $subscriber;
       }
 
@@ -206,6 +209,8 @@ class Subscriber extends Model {
       }
     }
 
+    $subscriber = Source::setSource($subscriber, Source::FORM);
+
     if($subscriber->save()) {
       // link subscriber to segments
       SubscriberSegment::subscribeToSegments($subscriber, $segment_ids);