This gem prevents using friendly_id with non-translated slugs on some models of the same project

[thedarkside]

This gem adds a locale column to the friendly_id_slugs table with null: :false. This way it enforces slugs being translated project wide.

If one wants a translated slug with history on model A but a non-translated slug with history on model B the current behavior is the current locale is being saved for the non-translated slug on model B too!

This is due to the implementation of the slug_decorator only taking the existence of the locale column into account.

The current implementation of the friendly_id-mobility gem does not allow such a hybrid usage of the friendly_id gem but it should!

Suggestion:

• The usage of the :mobility plugin should be checked in the slug_decorator too!
• The not null constraint should be loosened up to allow locale being null for non-translated slugs.

What do you think?