DBConnect connects to postgres and returns the handle.

DeleteArea removes the user's pickup area from the areas table.

GetAreaID returns the id of an area given userID and the area.

GetPickupAreasWithinArea takes an area as a set of GPS points and returns all the trash pickup areas within it.

InsertArea adds the user's pickup area to the areas table and returns new ID.

we cannot use rs.LastInsertId() because its not supported by pq https://github.com/lib/pq/issues/24.