Add a warning to readme

README.md

@@ -4,6 +4,12 @@
 
 ## Production-like setup
 
+> [!IMPORTANT]
+> Note that running Indico inside Docker is not officially supported. The
+> configuration described here serves only as an example of how Indico might be
+> deployed with Docker. For more information, see our official installation
+> guides [here](https://docs.getindico.io/en/stable/installation/).
+
 ### Quickstart
 
 Before starting the containers, set a `SECRET_KEY` in the [`indico-prod/indico.conf`](indico-prod/indico.conf) file. You can generate one by running the following snippet from the terminal: