These indexes are not recorded in the WAL (at least until PostgreSQL
10) and this isn't worth the minor performance improvement over btree
indexes.

This module provides a class method called `each_batch` that can be used
to iterate tables in batches in a more efficient way compared to Rails'
`in_batches` method. This commit also includes a RuboCop cop to
blacklist the use of `in_batches` in favour of this new method.

This cop has been renamed to ActiveRecordSerialize to match the way
"ActiveRecord" is usually written.

This is allowed for existing instances so we don't end up 76 offenses
right away, but for new code one should _only_ use this if they _have_
to remove non database data. Even then it's usually better to do this in
a service class as this gives you more control over how to remove the
data (e.g. in bulk).

Resolves the `codeclimate` CI failure

This cop adds an offense when `before`, `after`, or `around` are used as
single-line blocks.