customize_event can't be set when using rails?

[krainboltgreene]

Latest ruby, latest rails, latest logstash-logger

  if ENV.key?("LOGSTASH_ORIGIN")
    config.autoflush_log = true

    config.logstash.uri = ENV.fetch("LOGSTASH_ORIGIN")
    config.logstash.customize_event do |event|
      event.merge!({
        "application-name" => "sr-warehouse"
      })
    end
  end

Doesn't seem to set the property on logging.