We were very inconsistent regarding these rules.
Personally I prefer no empty lines around blocks, clases, etc... as
recommended by the Ruby style guide [1], and they're the default values
in rubocop, so those are the settings I'm applying.
The exception is the `private` access modifier, since we were leaving
empty lines around it most of the time. That's the default rubocop rule
as well. Personally I don't have a strong preference about this one.
[1] https://rubystyle.guide/#empty-lines-around-bodies
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
