Updated header

The new header makes a bit more sense to me as a flow.
Merge pull request #1614 from jamtur01/patch-1

docs(docs/installing_deis/register-admin-user.rst): Change section header
fix(controller): don't encode empty JSON objects or arrays as strings

The django-json-field 0.5.5 package has a bug encoding empty JSON objects.
Instead use a subclass which fixes this as a special case.