Update Dockerfile

Dockerfile

@@ -17,9 +17,8 @@ RUN pip install flask gunicorn pymupdf tiktoken
 # Expose default port
 EXPOSE 7860
 
-# Run with Gunicorn (Flask / WSGI)
-CMD ["gunicorn", "app:app", \
-     "--bind", "0.0.0.0:${PORT}", \
-     "--workers", "1", "--threads", "4", "--timeout", "180", \
-     "--access-logfile", "-", "--error-logfile", "-", "--log-level", "debug", \
-     "--preload"]
+# Run with Gunicorn (Flask / WSGI) — allow $PORT expansion
+CMD ["sh", "-c", "gunicorn app:app \
+  --bind 0.0.0.0:${PORT:-7860} \
+  --workers 1 --threads 4 --timeout 180 \
+  --access-logfile - --error-logfile - --log-level debug --preload"]