Fix #140: Add support for offline development via auto-login backend.

Because I like littering my code with hyperbole and panic, I would add a warning here:

```
.. warning::
   Use of this creates an insecure site! Do not use on a publicly-visible server! FOR REALZ!!! DON'T
   DO IT! YOU COULD BE EXCOMMUNICATED AND DIE OF DYSENTERY!
```