pyard-service Docker changes

 - import pyard on start, not build
 - use a docker-entrypoint script to start the app
 - update Makefile to produce versioned docker image

Author: pbashyal-nmdp

docker-entrypoint-flask.sh

@@ -0,0 +1,16 @@
+#!/bin/sh
+set -e
+
+# A positive integer generally in the 2-4 x $(NUM_CORES) range.
+WORKER_PROCESSES=${WORKERS:-4}
+
+echo "Starting Magenta with" "${WORKER_PROCESSES}" worker processes.
+
+if [ "${WORKER_PROCESSES}" != "1" ]; then
+  WORKER_FLAG="--workers=${WORKER_PROCESSES}"
+fi
+
+# Import pyard before starting the app
+pyard-import
+
+gunicorn --preload --bind 0.0.0.0:8080 --timeout 5000 --log-level info "${WORKER_FLAG}" app:app