Create apply_tags

[Nosferican]

Draft!

[parente]

@Nosferican Thanks for submitting this. The code you submitted looks right. We don't have any automated testing setup for the docker hub hooks. In lieu of that, could you try running the few new commands that fetch the Julia and R versions locally to ensure they return the expected values?

In addition to this script, you'll need to add a couple lines like these found in base-notebook/hooks/post_push to the top of datascience-notebook/hooks/post_push to source the apply_tags file:

docker-stacks/base-notebook/hooks/post_push

Lines 4 to 6 in 414b5d7

	# Apply and push all tags
	source hooks/apply_tags
	docker push $DOCKER_REPO

After confirming the commands work and adding those extra lines, I think this is good to merge and try.

[Nosferican]

jovyan@381b43ea26a5:~$ python --version 2>&1 | awk '{print $2}'
3.7.6
jovyan@381b43ea26a5:~$ R --version |  sed -n 1p | awk '{print $3}'
3.6.1
jovyan@381b43ea26a5:~$ julia --version | awk '{print $3}'
1.3.1
jovyan@381b43ea26a5:~$ jupyter-notebook --version | tr -d '\r'
6.0.3
jovyan@381b43ea26a5:~$ jupyterhub --version | tr -d '\r'
1.1.0
jovyan@381b43ea26a5:~$ jupyter-lab --version | tr -d '\r'
1.2.5

[parente]

@Nosferican I think there's a couple copy/paste errors in your last commit. If you accept those two tag name changes, I think we're good to merge.

[parente]

@Nosferican Thanks for sending this PR and working through improving it. 🍰

Let's merge it and see how it goes. If there are problems when Docker Hub attempts to build the image, we might need to iterate. I'll comment back here with the results since the build logs are, unfortunately, private.

[parente]

I fixed a small error missed during code review with a direct comment to master: 9f4983c#diff-57bd71ca260fa0afd2753f51e94b8420