Update rejoin-user-events.js

Author: rebeccaellis

retail/interactive-tutorials/events/rejoin-user-events.js

@@ -11,6 +11,7 @@
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
+// [START retail_rejoin_user_events]
 
 'use strict';
 
@@ -72,3 +73,5 @@ process.on('unhandledRejection', err => {
 });
 
 main();
+
+// [END retail_rejoin_user_events]