Constants vs. class methods

Greetings,
I would like to hear some community standpoint regarding this matter.

class User < ActiveRecord::Base
  ROLES = %w(admin moderator contributor)
end

# > User::ROLES
# => ["admin", "moderator", "contributor"]

or...

class User < ActiveRecord::Base
  self.roles
    @roles ||= %w(admin moderator contributor)
  end
end

# > User.roles
# => ["admin", "moderator", "contributor"]

I personally prefer class methods since this approach looks more object-oriented to me while screaming snake cased constant feels kinda ugly typographically.

There is also interesting Stack Overflow discussion.

Start by comparing the two Ruby examples in the issue and reading the linked Stack Overflow discussion. The task is to establish a project style-guide position on constants versus class methods; it is done when the community reaches a decision and the guidance is recorded in the style guide.