add db_index to narrative object_id
add db_index to narrative object_id

zimmerman-zimmerman/OIPA,zimmerman-zimmerman/OIPA,openaid-IATI/OIPA,zimmerman-zimmerman/OIPA,openaid-IATI/OIPA,zimmerman-zimmerman/OIPA,openaid-IATI/OIPA,zimmerman-zimmerman/OIPA,openaid-IATI/OIPA,openaid-IATI/OIPA