title: How to define schema for an ActiveRecord model?
body: <p>I can find how to define columns only when doing migrations.</p>
  
  <p>However i do not need to migrate my model.</p>
  
  <p>I want to work with it "virtually".</p>
  
  <p>Does AR read columns data only from db?</p>
  
  <p>Any way to define columns like in DataMapper?</p>
  
  <pre><code>class Post
    include DataMapper::Resource
  
    property :id,        Serial 
    property :title,     String
    property :published, Boolean
  end
  </code></pre>
  
  <p>Now i can play with my model without migrations/connections.</p>