Show repository in Differential emails

Summary: Ref T5137. Listing the repository in Differential emails makes it easy to filter.

Test Plan: Eye-ball it.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: young_hwi, epriestley, Korvin

Maniphest Tasks: T5137

Differential Revision: https://secure.phabricator.com/D9609

src/applications/differential/customfield/DifferentialRepositoryField.php

@@ -143,4 +143,26 @@ final class DifferentialRepositoryField
     return $this->renderHandleList($handles);
   }
 
+  public function shouldAppearInTransactionMail() {
+    return true;
+  }
+
+  public function updateTransactionMailBody(
+    PhabricatorMetaMTAMailBody $body,
+    PhabricatorApplicationTransactionEditor $editor,
+    array $xactions) {
+
+    if (!$editor->getDiffUpdateTransaction($xactions)) {
+      return;
+    }
+
+    $repository = $this->getObject()->getRepository();
+    if ($repository === null) {
+      return;
+    }
+
+    $body->addTextSection(pht('REPOSITORY'),
+      $repository->getMonogram().' '.$repository->getName());
+  }
+
 }