article.rb

# encoding: utf-8

class Article
  attr_accessor :title, :body
   
  def initalize(title, body)
    self.title = title
    self.body = body
  end
end

article_repository.rb

# encoding: utf-8

class ArticleRepository < ActiveRecor::Base
  
end

save_article.rb

# encoding: utf-8

class SaveArticle
  def initalize(article)
    @article = article
  end
  
  def call
    repos = ArticleRepository.find(@article.id)
    repos.body  = @article.body
    repos.title = @article.title
    repos.save!
  end
end