Remove no longer required currently_migrating? helper method
Remove no longer required currently_migrating? helper method

Our production migration hook which preloads the entire application
to see if any views have pending changes only triggers when
`create_enabled` is false.

In development mode, `create_enabled` is true but migrations
should not be loading application code so this check should
not be needed.

jasoncodes/activerecord_views,jasoncodes/activerecord_views