hash({email}) {
        return crypto.createHash('sha256').update(email, 'utf8').digest('hex');
      }
NOTE: SQLITE creates an index on the `primaryKey` (the ID) for you.
This "Auto Index" is called `sqlite_autoindex_contacts_1`.

If you run `EXPLAIN QUERY PLAN SELECT * FROM contacts WHERE id=1` you
get:
  SEARCH TABLE contacts USING INDEX sqlite_autoindex_contacts_1
(id=?)