doc: add diagram

README.md

@@ -30,11 +30,15 @@ A Jitsi Meet installation can be broken down into the following components:
 * A conference focus component
 * A video router (could be more than one)
 
+![](resources/docker-jitsi-meet.png)
+
+The diagram shows a typical deployment in a host running Docker, with a separate container
+(not included in this project) which acts as a reverse proxy and SSL terminator, then
+passing the traffic to the web container serving Jitsi Meet.
+
 This project separates each of the components above into interlinked containers. To this end,
 several container images are provided.
 
-TODO: image.
-
 ### Images
 
 * **base**: Debian stable base image with the [S6 Overlay] for process control and the