Basic stub creation

Quick and dirty implementation of /stubs/create, including redirection
to the created stub after it's been made. That should be reevaluated when we
actually know how people end up admining stubs -- you probably want to stay on
the creation form so you can put a bunch in in a row

The templates are currently completely unstyled.
Hoist stub db interaction out of the views

Pulls db interaction out of views into a few functions that work alongside
a Stub model. I prefer not having db interaction in the views so we can muck
with view logic without having to see all the sql floating around.
Make stubs creatable by staff

Per discussion on makyo/ideawheel#38, staff should be able to create stubs.
We consider admins to be staff for now so is_staff() in user.py will give us
true for either one.
Merge pull request #38 from jculpon/stubs

Basic stub interations