Document how to enable the push notifications service.

docker-compose.yml

@@ -50,5 +50,7 @@ services:
       SETTING_EMAIL_USE_SSL: "False"
       SETTING_EMAIL_USE_TLS: "True"
       ZULIP_AUTH_BACKENDS: "EmailAuthBackend"
+      # Uncomment this when configuring the mobile push notifications service
+      # SETTING_PUSH_NOTIFICATION_BOUNCER_URL: 'https://push.zulipchat.com'
     volumes:
       - "/opt/docker/zulip/zulip:/data:rw"

kubernetes/zulip-rc.yml

@@ -98,6 +98,9 @@ spec:
           value: "zulip"
         - name: SSL_CERTIFICATE_GENERATION
           value: "self-signed"
+        # Uncomment this when configuring the mobile push notifications service
+        # - name: PUSH_NOTIFICATION_BOUNCER_URL
+        # value: 'https://push.zulipchat.com'
         ports:
         - containerPort: 80
           name: http