Update README with docker usage

README.md

@@ -45,6 +45,62 @@ curl -v -x 127.0.0.1:8080 http://www.example.com
 
 Proxy listens on `127.0.0.1:8080` by default. Use `-L` (or `--listen-address`) CLI option to change this.
 
+## Docker usage
+
+You may use a docker image too if you'd like:
+
+```bash
+# Run the proxy in background
+docker run -d --name=etc-hosts-proxy -p 8080:8080 --rm \
+  -e ETC_HOSTS_PROXY_HOSTS_LIST="akamai.com=2.21.250.7,www.akamai.com=2.21.250.7" \
+  -e ETC_HOSTS_PROXY_DEBUG=true \
+  ghcr.io/jay7x/etc-hosts-proxy:latest
+
+curl -v -x 127.0.0.1:8080 http://akamai.com
+
+docker logs etc-hosts-proxy
+```
+
+NOTE: You should not use 127.0.0.1 (or ::1) as your redirection target in the hosts list while running in a container. This will redirect the request to the container's localhost, which is not what you might expect.
+
+A bit more complex example to redirect some domains to a nginx container:
+
+```bash
+# Create a docker network
+docker network create somenet
+
+# Run a web server exposed in somenet and on 0.0.0.0:8080 on the host
+docker run -d --name=nginx --net=somenet -p 8080:80 --rm nginx:latest
+
+# Run the proxy connected to somenet and exposed on 0.0.0.0:3128 on the host
+docker run -d --name=etc-hosts-proxy --net=somenet -p 3128:8080 --rm \
+  -e ETC_HOSTS_PROXY_HOSTS_LIST="example.com=nginx,www.example.com=nginx" \
+  -e ETC_HOSTS_PROXY_DEBUG=true \
+  ghcr.io/jay7x/etc-hosts-proxy:latest
+
+# Check nginx
+curl -v http://127.0.0.1:8080
+
+# Check proxy is proxying (note the port is 3128 here)
+curl -v -x 127.0.0.1:3128 http://example.com
+curl -v -x 127.0.0.1:3128 http://www.example.com
+# This should not be redirected
+curl -v -x 127.0.0.1:3128 http://example.net
+
+# Check logs
+docker logs proxy
+docker logs nginx
+
+# Cleanup
+docker stop proxy
+docker stop nginx
+docker network rm somenet
+```
+
+Docker images are built by `goreleaser` from the [Dockerfile](https://github.com/jay7x/etc-hosts-proxy/blob/main/.dockerfile)
+
+See [etc-hosts-proxy Github Container registry](https://github.com/jay7x/etc-hosts-proxy/pkgs/container/etc-hosts-proxy) for more details
+
 ## Environment variables
 
 | Variable | Description |