fix: update Dockerfile and documentation for APT_CACHER_NG configuration

Dockerfile

@@ -5,11 +5,9 @@ FROM python:3.11-slim-bookworm
 ENV PYTHONUNBUFFERED=1
 ENV PYTHONDONTWRITEBYTECODE=1
 ENV FLASK_ENV=production
-ENV FLASK_SECRET=production-secret-change-me
-ENV APT_CACHER_NG=http://192.168.88.14:3142
 
-# Add apt-cacher-ng configuration
+# Add apt-cacher-ng configuration (if APT_CACHER_NG is set)
-RUN echo 'Acquire::http { Proxy "'"$APT_CACHER_NG"'/"; };' > /etc/apt/apt.conf.d/01proxy
+RUN if [ -n "$APT_CACHER_NG" ]; then echo 'Acquire::http { Proxy "'"$APT_CACHER_NG"'/"; };' > /etc/apt/apt.conf.d/01proxy; fi
 
 # Install system dependencies
 RUN apt-get update && apt-get install -y \

README-Docker.md

@@ -58,7 +58,8 @@ This application is a Craigslist job scraper with a Flask web interface.
 ### Environment Variables
 
 - `FLASK_ENV`: Set to `production`
-- `FLASK_SECRET`: Secret key for Flask sessions
+- `FLASK_SECRET`: Secret key for Flask sessions (required)
+- `APT_CACHER_NG`: Optional URL for apt-cacher-ng proxy to speed up package downloads (e.g., `http://192.168.88.14:3142`)
 
 ### Database Configuration
 
@@ -309,6 +310,7 @@ services:
 
       # Optional configuration
       - GUNICORN_WORKERS=${GUNICORN_WORKERS:-4}
+      - APT_CACHER_NG=${APT_CACHER_NG}
     volumes:
       - type: bind
         source: ./cache

README.md

@@ -39,3 +39,7 @@ The application includes an automated scheduler that runs the job scraping proce
 - **Testing**: Comprehensive test suite in `tests/test_scheduler.py`
 
 To modify the scheduling interval, edit the `start_scheduler()` function in `web/craigslist.py`.
+
+## Docker Deployment
+
+Please see [README-Docker.md](README-Docker.md) for instructions on deploying the application using Docker.

docker-compose.yml

@@ -18,6 +18,7 @@ services:
 
       # Optional configuration
       - GUNICORN_WORKERS=${GUNICORN_WORKERS:-4}
+      - APT_CACHER_NG=${APT_CACHER_NG}
     volumes:
       - type: bind
         source: ./cache