Exemple d'un vieux sondage rejeté : GET /sondages/au-premier-tour-des-elections-presidentielles-de-la-republique-francaise-je-vais-voter => HTTP 500
F, [2016-11-03T12:39:47.894017 #25788] FATAL -- :
NoMethodError (undefined method `amr?' for nil:NilClass):
app/models/poll.rb:114:in `viewable_by?'
app/controllers/application_controller.rb:102:in `enforce_view_permission'
app/controllers/polls_controller.rb:23:in `show'