foos_controller.rb

class FoosController < ApplicationController
  include Pundit
  #...

  # record policy
  def set_record_policy
    policy(PolicyContext.new(record, current_user)
  end

  # scope policy
  def set_policy_scope
    policy_scope(PolicyContext.new(RecordClassName, current_user))
  end

  # authorizing controller action
  def authorize_action
    authorize PolicyContext.new(record, user), "#{action_name}?"
  end
end