9 seed data

**I'm putting this up so it can be reviewed.  Merge with caution or to test it out.  It will not break existing code.**

I've created the basic seed data.

It creates the 4 required users for testing, and 4 random addresses.

Assigning `categories` to items has proved very problematic as a results of the `HABTM` association.

The fabricators for `items` are commented out on lines `35-37` but can be run.  It generates multiple categories since they are not unique and I have not figured out how to fix that.

Notwithstanding all this, it does allow us to have working data to see in views.

Invoking the seeds file requires running the following rake tasks:

```
rake db:drop
rake db:create
rake db:migrate
rake db:seed
```