Drop override, add README clarification

README.md

@@ -1,3 +1,10 @@
 # renovate
 
 > https://renovate.whitesourcesoftware.com
+
+Renovate is running in a cron job in the swarm and scanning git repositories
+specified in the [config.js](./configs/prod/config.js.tmpl) in order to
+automatically submit pull requests for dependency upgrades. Renovate supports
+[multiple languages and frameworks](https://docs.renovatebot.com) (see
+"Language support"). This helps us keep our Docker file tags and Compose
+versions update to date, amongst other things.

docker-compose.override.yml

@@ -1,4 +0,0 @@
----
-version: "3.8"
-
-services: