Give users ping

[rsignell-usgs]

I'm trying to figure out a problem with globus and it would be useful to have ping available.
On ubuntu, this is

apt-get install iputils-ping

https://superuser.com/a/853376

[isuftin]

@rsignell-usgs Considering what we've learned in #18 - is this still necessary? It seems that if the provider of the AWS account opens port 2223 externally, that issue should be resolved and having ping would no longer be necessary. Thoughts?

The reason I hold off is because adding ping or any other utilities you'd need to have would require creating a new Docker image of the single-user notebook and would need to replace your current environment by blowing away your current running notebook and have you log into the new one.

Let me know your thoughts.