## User Model
class User < ActiveRecord::Base
  has_many :articles, :dependent => :destroy
end

## Article Model
class Article < ActiveRecord::Base
  belongs_to :user
end

## IRB
irb(main):002:0> u = User.find(:first)
=> #<User id: 1, username: "Blinchik", password: "1234", created_at: "2008-04-19 17:57:24", updated_at: "2008-04-19 17:57:24">
irb(main):007:0> a = u.articles.create(:author => u.username, :title => "JHGhgas")
=> #<Article id: nil, author: "Blinchik", title: "JHGhgas", body: nil, user_id: 1, created_at: nil, updated_at: nil>
irb(main):007:0> a.save
=> nil
irb(main):008:0> Article.find(:all)
=> []