added flit to dockerfile

Dockerfile

@@ -30,6 +30,7 @@ WORKDIR /app
 RUN pip install --upgrade pip
 RUN pip install gunicorn
 RUN pip install wheel
+RUN pip install flit
 
 RUN pip install -r requirements.txt
 RUN flit install --pth-file

requirements.txt

@@ -0,0 +1,6 @@
+openpyxl==3.0.5
+pyramid==1.10.4
+pyramid-jinja2==2.8
+pyramid-mailer==0.15.1
+waitress==1.4.4
+passlib==1.7.2