Voting PIN — DB Upgrade

✘ Added pin_code column to election_checkins: SQLSTATE[42S21]: Column already exists: 1060 Duplicate column name 'pin_code'

✘ Added pin_used column to election_checkins: SQLSTATE[42S21]: Column already exists: 1060 Duplicate column name 'pin_used'

✘ Added unique index on (election_id, pin_code): SQLSTATE[42000]: Syntax error or access violation: 1061 Duplicate key name 'unique_election_pin'