add repo and tag to image code example
Example 1: docker tag
docker tag SOURCE_IMAGE[:TAG] TARGET_IMAGE[:TAG]
Example 2: how to change the tag of docker image
docker tag 7b9b13f7b9c0 ubuntu/dev:v1.6.14.2017
docker tag SOURCE_IMAGE[:TAG] TARGET_IMAGE[:TAG]
docker tag 7b9b13f7b9c0 ubuntu/dev:v1.6.14.2017