Amend Sluggable module

[ferblape]

Sluggable module works fine, but it can be improved a bit:

1. The callback that sets the slug should be before_validation. This way, it will work not only after creating but after updating

2. The module should include two validations:

• validate the presence of the slug
• validate the uniqueness of the slug in the scope of the site

[amiedes]

I have a concern about this concern .

If I remember right, the reason why I used before_create was because the slug shouldn't be null (there is a DB constraint for this). This way, when a user doesn't specify a slug in the interface, it gets auto-assigned when the record is created for the first time.

So, a before_validation is not strictly needed, but adding it won't change the current behavior.

[ferblape]

After discussing with @amiedes I have updated the issue.

[apradillap]

Keep in mind when we do the issue that as it has an after_create, in the case, objects like PersonPost the method attributes_for_slug

    def attributes_for_slug
      [created_at. strftime ("%F"), title]
    end

It has an attribute that we haven't in the before_validation and we will have to omit the creation_at for the slug no? cc @ferblape

[ferblape]

Good point, let's us Time.now.