Fix Ponder exception for adding comments

Summary: Fixes T2323. Prior to search refactoring (I think), this stuff was loaded implicitly. Now load it explicitly.

Test Plan: Added a comment to a Ponder answer without an exception.

Reviewers: btrahan, vrana

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T2323

Differential Revision: https://secure.phabricator.com/D4536

src/applications/ponder/controller/PonderCommentSaveController.php

@@ -16,6 +16,8 @@ final class PonderCommentSaveController extends PonderController {
       return new Aphront404Response();
     }
 
+    $question->attachRelated();
+
     $target = $request->getStr('target');
     $objects = id(new PhabricatorObjectHandleData(array($target)))
       ->setViewer($user)