add missing requirement and update Dockerfile to point to cherrypi and keep pip up-to-date

app/rest/Dockerfile

@@ -1,6 +1,7 @@
 FROM python:3-slim
 WORKDIR /usr/src/app
 COPY app/rest/requirements.txt ./
-RUN pip install --no-cache-dir -r requirements.txt
+RUN python3 -m pip install --upgrade pip && \
+    python3 -m pip install --no-cache-dir -r requirements.txt
 COPY app ./app
-CMD [ "python", "-m", "app.rest.pyapi" ]
+CMD [ "python", "-m", "app.rest.cherrypy" ]

app/rest/requirements.txt

@@ -1,4 +1,5 @@
 seaborn
 psycopg[binary]
 bottle
+wsgigzip
 cherrypy