Configure /data as a volume.

Dockerfile

@@ -26,8 +26,7 @@ COPY . .
 # Create the SQLite database directory with proper permissions
 RUN mkdir -p /app/instance && chmod 777 /app/instance
 
-RUN mkdir /data
-RUN chmod 777 /data
+VOLUME /data
 
 # Expose the port the app runs on
 EXPOSE 5000