add a first pass at a note on gunicorn tuning

As noted in #49 (closed), we had some useful documentation on gunicorn tuning hidden away in a comment. We're doing some more investigation work at the moment on gunicorn so free the existing comment from its prison as a note so that it can be worked on a bit more.

Closes #49 (closed)

changed milestone to %Sprint 101

approved this merge request

mentioned in commit 484925c3

merged