Install requirements first and then copy the code to make good use of

docker cache.

Dockerfile

@@ -2,12 +2,13 @@ FROM python:3.7
 
 WORKDIR /code
 
-# copy everything into /code
-COPY . .
-
 # install dependencies
+COPY ./requirements.txt ./
 RUN pip3 install --no-cache-dir -r requirements.txt
 
+# copy everything else into /code
+COPY . .
+
 EXPOSE 7777
 
 #gunicorn wsgi:app -b 0.0.0.0:7777 -w 2 --timeout 15 --log-level DEBUG