public function doRun()
 {
     if (!class_exists('MergeUser')) {
         throw new Exception('Extension:UserMerge is not installed');
     }
     $from = $this->params['from'];
     $to = $this->params['to'];
     $this->updateStatus('inprogress');
     $toUser = $this->maybeCreateNewUser($to);
     $renamingUser = $this->getRenameUser();
     foreach ($from as $olduser) {
         // Merge the users in order
         $um = new MergeUser(User::newFromName($olduser), $toUser, new UserMergeLogger(), MergeUser::USE_MULTI_COMMIT);
         $um->merge($renamingUser);
         $um->delete($renamingUser, 'wfMessage');
     }
     $this->done();
     return true;
 }