add a script to do retag latest tag

Author: chusiang

bin/retag_latest.sh

@@ -0,0 +1,16 @@
+#!/bin/bash
+
+echo 'Pull alpine image.'
+docker pull chusiang/ansible-jupyter:alpine-3.4
+echo
+
+echo 'Tag alpine image to latest.'
+docker tag  chusiang/ansible-jupyter:alpine-3.4 chusiang/ansible-jupyter:latest
+echo
+
+echo 'Push the latest tag.'
+docker push chusiang/ansible-jupyter:latest
+echo
+
+echo 'Remove old image.'
+docker rmi $(docker images | grep 'chusiang/ansible-jupyter' | grep '<none>' | awk '{ print $3 }')