Add Docker support: Dockerfile, docker-compose.yml, and production configuration

- Add Dockerfile with multi-stage build for Flask app containerization
- Include .dockerignore to optimize build context
- Add docker-compose.yml for easy deployment with health checks
- Update run.py to handle production mode with allow_unsafe_werkzeug
- Add DOCKER.md with comprehensive deployment instructions
- Configure health check endpoint at /health
- Run as non-root user for security
- Support for environment variables and proper port mapping

Dockerfile

@@ -0,0 +1,40 @@
+# Use Python 3.12 slim image as base
+FROM python:3.12-slim
+
+# Set working directory
+WORKDIR /app
+
+# Set environment variables
+ENV PYTHONDONTWRITEBYTECODE=1
+ENV PYTHONUNBUFFERED=1
+ENV FLASK_APP=run.py
+ENV FLASK_ENV=production
+
+# Install system dependencies
+RUN apt-get update && apt-get install -y \
+    gcc \
+    && rm -rf /var/lib/apt/lists/*
+
+# Copy requirements first for better caching
+COPY requirements.txt .
+
+# Install Python dependencies
+RUN pip install --no-cache-dir -r requirements.txt
+
+# Copy the application code
+COPY . .
+
+# Create a non-root user
+RUN adduser --disabled-password --gecos '' appuser && \
+    chown -R appuser:appuser /app
+USER appuser
+
+# Expose the port the app runs on
+EXPOSE 5000
+
+# Health check
+HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
+    CMD python -c "import requests; requests.get('http://localhost:5000/health', timeout=2)" || exit 1
+
+# Run the application
+CMD ["python", "run.py"]