Create indices for workertypes on both tables

[jhford]

We search by worker type fairly commonly, so I would like to index that value

[jhford]

the new sorter function is required because using the index changes the ordering of the entries inside of the database. The arrays aren't ordered, but we don't really have a way to represent a set easily here.

[petemoore]

Sorry I didn't do a good job of reviewing here. 😞