Add Guide for Theta

[katyhuff]

This repository's issues are reserved for feature requests, and bug reports, and questions.

I'm submitting a ...

• feature request

Expected Behavior

Ideally, just like there is a Using Blue Waters page on the arfc site, there should be a Using Theta page (perhaps at http://arfc.github.io/manual/guides/theta). It should describe where to go to request an account, where to find information about logging in, and eventually, how to load key environment settings (as are being developed in #214 ).

Actual Behavior

There is not yet a Using Theta page.

How can this issue be closed?

This issue can be closed with a merged PR that introduces as Using Theta page to the guides at arfc.github.io.

[munkm]

I think @gwenchee or @smpark7 would be good options for this issue since they're currently using Theta!

[munkm]

@yardasol once you're on Theta you would be a good candidate for this one too.