How to add user information to Airbrake notifications?

I have a Rails app which is sending Airbrake notifications fine, but I want to add some user information to the notifications.

I'm using the airbrake gem, v5.7.1, which adds a middleware to capture uncaught exceptions and report them before re-raising.

I tried, as per the README, to add a filter, to an initializer:

class UserDetailsFilter
  def call(notice)
    if notice.stash.has_key?(:rack_request)
      user_credentials = notice.stash[:rack_request].cookies["user_credentials"]          
      unless user_credentials.blank?
        user_id = user_credentials.split(':').last
        user = User.find(user_id)
        notice[:params][:user_email] = user.email
        notice[:params][:user_name] = "#{user.first_name} #{user.last_name}"
      end
    end 
  end
end

Airbrake.add_filter(UserDetailsFilter.new)

Using binding.pry I can confirm that this code is run and that notice does have the :params hash modified. However the params in the Airbrake UI only have action and controller information.

This was a bug in the Airbrake gem which has been fixed and was released in Airbrake 5.8.0.