gem 'wisper-activerecord'

class Meeting < ActiveRecord::Base
end

Wisper::ActiveRecord.subscribe(Meeting, to: Auditor.new)

class Auditor
  include Singleton

  attr_accessor :audt

  def initialize
    @audit = []
  end

  def on_create(subject)
    audit.push(audit_for(‘create’, subject))
  end

  def on_update(subject)
    audit.push(audit_for(‘update’, subject))
  end

  def on_destroy(subject)
    audit.push(audit_for(‘destroy’, subject))
  end

  def self.audit
    instance.audit
  end

  private

  def audit_for(action, subject)
    {
      action: action,
      subject_id: subject.id,
      subject_class: subject.class.to_s,
      changes: subject.changes,
      created_at: Time.now
    }
  end
end

Meeting.create(:description => ‘Team Retrospective’, :starts_at => Time.now + 2.days)

meeting = Meeting.find(1)
meeting.starts_at = Time.now + 2.months
meeting.save

Auditor.audit # => […]