add: doc for helm chart

Author: vipul-sharma20

README.md

@@ -16,6 +16,8 @@ Check usage and API further in the README.
 
 ## Deployment
 
+### Docker
+
 ```
 docker-compose up
 ```
@@ -24,6 +26,10 @@ Pre-built image at: https://hub.docker.com/repository/docker/vipul20/slack-stand
 
 Make sure to update the following environment variables in [`docker-compose.yml`](./docker-compose.yml)
 
+### Helm
+
+Helm chart in [`./charts`](./charts) directory.
+
 #### Slack tokens
 
 - `SLACK_SIGNING_SECRET`: Slack signing secret