* Run rubocop --autocorrect on app/, config/ and lib/, also manually fix some remaining style issues
* Run rubocop --autocorrect-all on db/
* Run rubocop --autocorrect-all on `spec/` and fix remaining issues
There were some concerns with the custom filter migration script dropping a table,
thus making it unsafe to run in a zero-downtime setting. Upstream introduced
a way to run migrations after deployment, so revisit the old migration script to
make use of this.