class History include Mongoid::Document field :me, type: String field :_with, type: String embeds_many :messages, cascade_callbacks: true accepts_nested_attributes_for :messages index({ me: 1, _with: 1 }, { unique: false }) def self.find_me_with(me, with) where(me: me, _with: with).limit(1).first end def self.save_message(me, from, message, chat_with, chat_id = nil) _with = chat_id.blank? ? chat_with : chat_id history = find_me_with(me, _with) history = History.new(me: me, _with: _with) if history.nil? record = Message.new(message: message, from: from) history.messages << record history.save end end