Add rayankans@ to background_sync watchlist

TBR=peter@chromium.org

Change-Id: I94aec74b3286c8d09f2e36a97c87aea61df22fbb
Reviewed-on: https://chromium-review.googlesource.com/c/1323451
Commit-Queue: Rayan Kanso <rayankans@chromium.org>
Reviewed-by: Rayan Kanso <rayankans@chromium.org>
Cr-Commit-Position: refs/heads/master@{#606124}

WATCHLISTS

@@ -1846,7 +1846,8 @@
                          'rayankans+watch@chromium.org',
                          'nator@chromium.org'],
     'background_sync': ['iclelland+watch@chromium.org',
-                        'peter@chromium.org'],
+                        'peter@chromium.org',
+                        'rayankans+watch@chromium.org'],
     'banners': ['dominickn+watch-banners@chromium.org',
                 'hanxi+watch@chromium.org',
                 'pkotwicz+watch@chromium.org'],