docker build updates to improve security

Dockerfile

@@ -1,9 +1,23 @@
 # Dockerfile for Reddit Test Posts Bot
 FROM python:3.11-slim
+
+# Create a non-root user for running the bot
+RUN groupadd -g ${GROUP_ID:-1000} botgroup && \
+    useradd -u ${USER_ID:-1000} -g botgroup -m botuser
+
 WORKDIR /app
 COPY requirements.txt .
 RUN pip install --no-cache-dir -r requirements.txt
+
 COPY bot.py .
 COPY config.py .
+
+# Create DB directory with proper permissions
+RUN mkdir -p /app/DB && chown -R botuser:botgroup /app
+
 ENV PYTHONUNBUFFERED=1
+
+# Switch to non-root user
+USER botuser
+
 CMD ["python", "bot.py"]