jitsi-component-selector, docs: pull and run from registry

jitsi-component-selector/README.md

@@ -2,7 +2,8 @@
 
 ## Run
 
-Assumed that the host IP is `172.17.17.1`.
+- This service needs `Redis` and `ASAP key server`.
+- Assumed that the host IP is `172.17.17.1`.
 
 Run the following in this folder but in a different shell to simulate ASAP key
 server.
@@ -14,6 +15,20 @@ python3 -m http.server -d ../files/asap 8000
 ```bash
 docker run -d -p 6379:6379 redis
 
+docker pull ghcr.io/jitsi-contrib/docker-images/jitsi-component-selector:latest
+
+docker run \
+  -p 8015:8015 \
+  -e REDIS_HOST=172.17.17.1 \
+  -e PROTECTED_SIGNAL_API=true \
+  -e SYSTEM_ASAP_BASE_URL_MAPPINGS='[{"kid": "^jitsi/(.*)$", "baseUrl": "http://172.17.17.1:8000/server"}]' \
+  -e SIGNAL_ASAP_BASE_URL_MAPPINGS='[{"kid": "^jitsi/(.*)$", "baseUrl": "http://172.17.17.1:8000/signal"}]' \
+  ghcr.io/jitsi-contrib/docker-images/jitsi-component-selector
+```
+
+## Build and Run
+
+```bash
 docker image build -t jitsi-component-selector .
 
 docker run \