We like to stay as close as possible to latest with rubocop cause the cops
get better.
This update required some code changes, specifically the default is to avoid
explicit returns where implicit is done
Also this renames a few rules
This reduces chances of errors where consumers of strings mutate inputs
and reduces memory usage of the app.
Test suite passes now, but there may be some stuff left, so we will run
a few sites on a branch prior to merging
This changes the content of `@categories_lookup` from `Category` objects
to IDs since the category names aren't needed anymore. The lookup
method has been renamed too.
