add prefetch_related to BillImporter, related to #108
add prefetch_related to BillImporter, related to #108

rshorey/pupa,influence-usa/pupa,mileswwatkins/pupa,mileswwatkins/pupa,influence-usa/pupa,opencivicdata/pupa,datamade/pupa,datamade/pupa,rshorey/pupa,opencivicdata/pupa