Fix database config to match production naming
Fix database config to match production naming

Production DB uses the prefix `policy-publisher`, which is
convention for most of our apps, in puppet, etc.

The typo here meant the sync of the proruction DB wasn't
replacing the right DB locally.

https://github.gds/gds/alphagov-deployment/blob/master/policy-publisher/to_upload/config/production/database.yml#L7

alphagov/policy-publisher,alphagov/policy-publisher,alphagov/policy-publisher,alphagov/policy-publisher