てめー　ブッ殺す！　『アクティブ・レコード』ッ！

ar_test.rb

require "active_record"

ActiveRecord::Base.establish_connection(
    :adapter => 'sqlite3',
    :database => './test.sqlite3'
)

class UsersInit < ActiveRecord::Migration
    def self.up
        create_table( :users ) do |t|
            t.string :user_name, :null => false
            t.string :twitter_id, :limit => 25, :null => false
            t.timestamps
        end
    end
    def self.down
        drop_table :users
    end
end

UsersInit.migrate(:up) if File.exist?("./test.sqlite3")

class User < ActiveRecord::Base
    def to_s
        "#{user_name}(#{twitter_id}), up:#{updated_at}"
    end
end

User.create( :user_name => "inutano", :twitter_id => "iNut" )
User.create( :user_name => "benjo", :twitter_id => "y_benjo")
User.create( :user_name => "yag", :twitter_id => "yag_ays")

User.find( :all ).each do |user|
    puts user.to_s
end