Update README-docker.md

README-docker.md

@@ -11,9 +11,32 @@ curl http://localhost:25500
 # if you see `subconverter vx.x.x backend` then the container is up and running
 ```
 
-If you want to update `pref.ini` inside the docker, you can use the following command:
+If you want to update `pref` configuration inside the docker, you can use the following command:
 ```bash
 # assume your configuration file name is `newpref.ini`
 curl -F "@data=newpref.ini" http://localhost:25500/updateconf?type=form&token=password
 # you may want to change this token in your configuration file
 ```
+
+For those who want to use their own `pref` configuration and/or rules, snippets, profiles:
+```txt
+# you can save the files you want to replace to a folder, then copy it into to the docker
+# using the latest build of the official docker
+FROM tindy2013/subconverter:latest
+# assume your files are inside replacements/
+# subconverter folder is located in /base/, which has the same structure as the base/ folder in the repository
+COPY replacements/ /base/
+# expose internal port
+EXPOSE 25500
+# notice that you still need to use '-p 25500:25500' when starting the docker to forward this port
+```
+Save the content above to a `Dockerfile`, then run:
+```bash
+# build with this Dockerfile and tag it subconverter-custom
+docker build -t subconverter-custom:latest .
+# run the docker detached, forward internal port 25500 to host port 25500
+docker run -d -p 25500:25500 subconverter-custom:latest
+# then check its status
+curl http://localhost:25500
+# if you see `subconverter vx.x.x backend` then the container is up and running
+```