Interim bill table population

README is updated with barebones instructions to manually pull bill data and populate ca_test.bill
small bug in bill table population: bill_id serial column value appears to be populating as "None"
next, chamber_vote_result table population is blocked since no valid bill_id value can be accessed to use as a foreign key
bill_history population logic to select from unique possible bill_number values has not been tested

techequitycollaborative / ca-leg-tracker