We're awfully sorry
If you're using the friendly_id gem in your rails project you've recognized the hyphen in the slug.
E.g. you registered a new user:
the slug will be foo-bar by default.
That is not comfortable for some reasons, an underscore will be the better solution.
Type in your model:
class User < ActiveRecord::Base
friendly_id :name, use: :slugged, :sequence_seperator => '_'