Мое приложение Rails возвращает 500, но я не вижу подробностей в журналах

Question

curl localhost: 3000 / groups дает

Started GET "/groups" for 193.160.199.32 at 2018-07-05 13:41:04 +0000
Processing by GroupsController#index as */*
Filter chain halted as :authenticate_user rendered or redirected
Completed 500 Internal Server Error in 94ms (Views: 0.1ms)

Но почему я не вижу больше деталей?

Я установил RAILS_ENV=staging

[1] pry(main)> Rails.env
=> "staging"

grep log config / environment / staging.rb

  config.log_level = :debug
  # Prepend all log lines with the following tags.
  config.log_tags = [:request_id]

  config.log_formatter = ::Logger::Formatter.new