Build KarlDNS self-hosted DynDNS service

Dockerfile

@@ -1,13 +1,15 @@
 FROM python:3.12-slim
 
+ENV DDNS_DATABASE=/data/ddns.sqlite3
+
 WORKDIR /app
 COPY pyproject.toml README.md /app/
 COPY router_dyndns /app/router_dyndns
 RUN pip install --no-cache-dir .
-RUN adduser --system --group --home /app routerpulse \
+RUN adduser --system --group --home /app karldns \
     && mkdir -p /data \
-    && chown -R routerpulse:routerpulse /app /data
-USER routerpulse
+    && chown -R karldns:karldns /app /data
+USER karldns
 
 EXPOSE 8080
-CMD ["router-dyndns", "serve", "--host", "0.0.0.0", "--port", "8080"]
+CMD ["karldns", "serve", "--host", "0.0.0.0", "--port", "8080"]