Refactoring gone wild:

1. Turns out I don't like the directory structure from that book: I'd rather keep the Express app entirely within the app folder.

2. Remove some empty directories; will recreate them when I understand what to put in them. (Later, much.)

3. Remove some dead code.

4. Partial implementation of various controller methods.

5. Move contents of db/ back into lib/ (where it used to be, where it has always belonged).

Code is a huge mess just now. Has no hope of starting up, let alone of doing the right thing....