title: Is there a Ruby on Rails generate migration statement to change "description" from string to text?
body: <p>It looks like <code>string</code> is limited to 256 characters and <code>text</code> is usually 65536 characters.</p>
  
  <p>I tried</p>
  
  <pre><code>ruby script/generate migration change_description_to_text description:text
  </code></pre>
  
  <p>but the <code>up</code> and <code>down</code> in the migration file generated are both empty?  Is there a way to generate this migration automatically?</p>
  
  <p>If added manually using a <code>remove_column</code> and an <code>add_column</code>, will all the old data be removed for the column?</p>