no issue
- `setId` is only used within the `events` plugin and it makes sense to
keep code together
- we don't lose anything by putting it here, but it should make it
easier to test in the future
no issue
- `formatOnWrite` doesn't override anything in Bookshelf but we use it
within the `override` plugin and sub-models may override it, so it's
easier to keep these things together
no issue
- we were only importing the `db` to access the `knex` instance, but
we can get this through the Bookshelf instance
- switches to pulling out `knex` from Bookshelf so we can remove the
remaining local require
