There are many possible ways to implement this feature:
* Adding a custom middleware
* Using rack-attack with a blocklist
* Using routes constraints
We're choosing to use a controller concern with a redirect because it's
what we do to handle unauthorized cancancan exceptions.
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
