Update README

Author: lahsivjar

README.md

@@ -11,6 +11,8 @@ Run using dockerhub image (note the variables in the command)
 docker run \
     -e "GRAFANA_URL=${grafana_url}" \
     -e "GRAFANA_API_KEY=${grafana_api_key}" \
+    -e "GRAFANA_GET_URL=${grafana_url}" \
+    -e "GRAFANA_POST_URL=${grafana_url}" \
     -e "GRAFONNET_PLAYGROUND_FOLDER_ID=${grafana_playground_folder_id}" \
     -e "GIN_MODE=release" \
     -p 8080:8080 \
@@ -19,6 +21,12 @@ docker run \
 
 *Note*: For debugging remove the `GIN_MODE` environment variable from above command
 
+## Cleaning up dashboards created by playground
+
+From version 1.0.0, grafonnet-playground allows automatically cleaning up the dashboards that were created. This can be configured via `AUTO_CLEANUP_INTERVAL` config and can be further tuned via other available configuration. For a list of all configurations please check [application.yml.sample](application.yml.sample) file.
+
+NOTE: Even when the dashboard is deleted after it has been rendered, it will continue to work and display data.
+
 ## Development build
 - Copy config file
 ```