title: Append an attribute to a model for temporary use on Rails 3
body: <p>I have a user model => <code>@user</code></p>
  
  <p>I want to add new attribute <code>current_time</code> to <code>@user</code> for temporary use.</p>
  
  <p>Don't want to do migration to add a column (just for temporary use):</p>
  
  <pre><code>@user.current_time = Time.now
  </code></pre>
  
  <p>Is there any way to achieve this?</p>
  
  <pre><code>NoMethodError (undefined method `current_time=' for #&lt;User:0x007fd6991e1050&gt;):
    app/controllers/carts_controller.rb:47:in `block in search_user'
    app/controllers/carts_controller.rb:45:in `search_user'
  </code></pre>