gistfile1.rb

class User < ActiveRecord::Base
  include ActiveModel::ForbiddenAttributesProtection

  has_secure_password

  has_many :topics, foreign_key: 'author_id'


  def unread_topics
    Topic
      .select('topics.*')
      .joins('LEFT JOIN read_marks ON read_marks.topic_id = topics.id AND read_marks.user_id = %d' % [ id ])
      .where('read_marks.id IS NULL OR read_marks.reply_id IS NULL OR read_marks.reply_id < topics.last_reply_id')
  end
end