aha! sorry, I lost $tuna last commit

Dockerfile

@@ -7,6 +7,6 @@ COPY requires.cpu .
 ARG tuna=https://pypi.tuna.tsinghua.edu.cn/simple
 
 RUN pip install --no-cache-dir --upgrade pip -i $tuna && \
- pip install --no-cache-dir -r requires.cpu -i
+ pip install --no-cache-dir -r requires.cpu -i $tuna
 
 CMD ["gunicorn", "app:app"]