use dedicated user

Dockerfile

@@ -6,7 +6,11 @@ COPY src/requirements.txt .
 COPY src/main.py .
 COPY src/message_processor.py .
 
-RUN pip install --no-cache-dir -r requirements.txt
+RUN \
+    addgroup -S appgroup && \
+    adduser -S appuser -G appgroup && \
+    apk add --no-cache bash && \
+    pip install --no-cache-dir -r requirements.txt
 
 
 ENV MQTT_BROKER=""
@@ -21,5 +25,7 @@ ENV DEFAULT_HIGH_TEMPERATURE=""
 ENV MAINTENANCE_TEMPERATURE=""
 ENV BOXES=""
 
+USER appuser
+
 CMD ["python", "main.py"]