make it more secure

Signed-off-by: Lennart Weller <lhw@ring0.de>

Dockerfile

@@ -1,9 +1,11 @@
 FROM python:3-alpine
 
-WORKDIR /asciiflow2
+WORKDIR /asciiflow
+RUN addgroup -S asciiflow && adduser -S asciiflow -G asciiflow -h /asciiflow
+USER asciiflow
 COPY . ./
 
 HEALTHCHECK CMD netstat -an | grep 8000 > /dev/null; if [ 0 != $? ]; then exit 1; fi;
 
 ENTRYPOINT ["python3", "-m", "http.server"]
-EXPOSE 8000
+EXPOSE 8000