post.rb

#models/post.rb

  class Post < ApplicationRecord
    belongs_to :user, touch: true
    after_save :create_json_cache

    
    def self.cache_key(posts)
    {
      serializer: 'posts',
      stat_record: posts.maximum(:updated_at)
    }
    end
    
    private

    def create_json_cache
      CreatePostsJsonCacheJob.perform_later
    end
  end