- Add web hook queue code back in. We'll remove it and turn it off after this CL goes to prod

- Make notification lookup always be by repo and its UUID, rather than the internal DB ID
- Add the init script for the notification worker

config.py

@@ -125,6 +125,9 @@ class DefaultConfig(object):
   DIFFS_QUEUE_NAME = 'imagediff'
   DOCKERFILE_BUILD_QUEUE_NAME = 'dockerfilebuild'
 
+  # TODO: Remove this in the prod push following the notifications change.
+  WEBHOOK_QUEUE_NAME = 'webhook'
+
   # Super user config. Note: This MUST BE an empty list for the default config.
   SUPER_USERS = []