title: Add Id column in a migration
body: <p>I have a Rails app, where one of the models does not have the <code>id</code> column. Doing some research I found the migration that created it:</p>
  
  <pre><code>create_table(:the_model, :id =&gt; false) do |t|
    # columns
  end
  </code></pre>
  
  <p>Now, on a new migration, I want to add the <code>id</code> column in a Rails standard way (not using database specific sql). How can I do that?</p>
  
  <p>I already tried this without success:</p>
  
  <pre><code>change_table(:the_model, :id =&gt; true) do |t|
  end
  </code></pre>