Request: Add 'zoo' package to docker image

[eeldren]

Could the 'zoo' package be added to the docker image? I use it for some more complex date/time finagling (and 'lubridate' doesn't quite do as much as I need it to).

Thanks!

[patr1ckm]

I think this is a reasonable addition, thank you! I'm looking to release in the next week or two.