You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: post.rb
    path of file: ./repos/thredded/app/models/thredded
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

module Thredded
  class Post < ActiveRecord::Base
    include Thredded::PostCommon
    include Thredded::ContentModerationState

    belongs_to :user,
               class_name: Thredded.user_class_name,
             
    
    def auto_follow_and_notify
      return unless user
      # need to do this in-process so that it appears to them immediately
      if first_post_in_topic? ? Thredded.auto_follow_when_creating_topic : Thredded.auto_follow_when_posting_in_topic
        UserTopicFollow.create_unless_exists(user.id, postable_id, :posted)
      end
      # everything else can happen later
      AutoFollowAndNotifyJob.perform_later(id)
    end