Slugs should only be updated on certain conditions, we need a trait that
meets that conditions and the name of the trait passed as a mandatory &
named argument on the sluggable concern
Why:
* We need certain models that use a Sluggable to generate a slug based on name attribute on save
How:
* Creating a shared example that knows how to create a factory of the described class
* Checking in it that new objects of the described class get the correct slug
