Docker enhancement

* optimizes image build dependency
* increases gunicorn default number of workers

Dockerfile

@@ -1,4 +1,4 @@
-FROM python:3.7
+FROM python:3.9-slim
 ENV PYTHONUNBUFFERED 1
 
 WORKDIR /konova

docker-entrypoint.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
-# Start all needed services inside the container!
-
+# Start all needed services once the container is fired up!
 service nginx start
 service redis-server start
 celery -A konova worker --detach
-gunicorn konova.wsgi:application --bind 0.0.0.0:8000
+# Rule of thumb: (2*CPU)+1 as worker_num -> Use 5 as default (matches a dual core)
+gunicorn --workers=5 konova.wsgi:application --bind=0.0.0.0:8000