While I don't use this feature, there are developers who do. It's useful
when running migrations and changing branches.
I'm raising an `ActiveRecord::IrreversibleMigration` exception in every
`drop_table` migration because these migrations were all done before
version 1.0.0, and so making all of them reversible would be too much
work for little benefit.
There are some rules which only affect migration files, and we cannot
enable them if we're excluding those files from being inspected.
We're also changing migrations related to the Rails/TimeZone rule
slightly because these fields were already changed afterwards, so we
aren't changing the schema.
DEPRECATION WARNING: Directly inheriting from ActiveRecord::Migration
is deprecated. Please specify the Rails release the migration was
written for:
class MigrationClass < ActiveRecord::Migration[4.2]
(called from require at bin/rails:4)
