missed a comma

diff --git a/bin/fetcher.php b/bin/fetcher.php
index af903ef78..d255d5452 100755
--- a/bin/fetcher.php
+++ b/bin/fetcher.php
@@ -1715,7 +1715,7 @@ class Fetcher implements CrawlConstants
             self::OPERATING_SYSTEM, self::MODIFIED, self::ROBOT_INSTANCE,
             self::LOCATION, self::SIZE, self::TOTAL_TIME, self::DNS_TIME,
             self::ROBOT_PATHS, self::GOT_ROBOT_TXT, self::CRAWL_DELAY,
-            self::AGENT_LIST, self::ROBOT_METAS, self::WARC_ID
+            self::AGENT_LIST, self::ROBOT_METAS, self::WARC_ID,
             self::CACHE_PAGE_VALIDATORS);

         foreach($summary_fields as $field) {