Fixed misleading instructions for docker image building

Dockerfile

@@ -0,0 +1,7 @@
+FROM python:3.13-slim
+RUN useradd --create-home --shell /bin/bash solarcontrol
+WORKDIR /script
+COPY solarcontrol.py ./
+RUN pip install --upgrade pip && pip3 install --no-cache-dir paho-mqtt python-dotenv requests
+USER solarcontrol
+ENTRYPOINT ["/usr/bin/python3", "solarcontrol.py"]

README.md

@@ -5,6 +5,14 @@ Enforce a zero export (or whatever consumption you like) policy with an OpenDTU-
 
 ## Configuring and usage
 
+
+### Docker
+
+Todo
+
+
+### Bare-bone
+
 The script can be configured using the .env file where you can adjust it (hopefully perfect) to your needs. After that, just run the script:
 
 ```bash
@@ -14,6 +22,18 @@ python3 lge320reader.py
 Please note: the .env file needs to be in the same folder or any other folder higher up in the directory structure as the script (more specifically, the WORKDIR). It is just a help, actually, the script searches for specific variables in its environment variables. It only loads the .env file so that you do not need to `export` all the files before running (see https://pypi.org/project/python-dotenv/ for more details). This also means that when using it in docker, you can set the docker containers environment file to that .env file and it will be accepted too.
 
 
+## Building docker
+
+To build the image for docker, simply use the following commands:
+
+```bash
+docker login  # login to docker hub
+docker buildx create --name buildx-multi-arch
+docker buildx use buildx-multi-arch
+docker buildx build --no-cache --platform linux/amd64,linux/386,linux/arm/v5,linux/arm/v7,linux/arm64/v8,linux/ppc64le,linux/s390x -t bluefox42/solarcontrol:<TAGNAME> . --push
+```
+
+
 ## License
 
 This project is licensed under the terms of the GNU General Public License v3.0 or later, see [COPYING](COPYING).