title: Force max length for string in PostgreSQL
body: <p>I am using heroku for a RoR application and am trying to manually set the length of a string column and am having trouble.</p>
  
  <p>I tried making a migration along the lines of </p>
  
  <pre><code>change_column :posts, :content, :string, :length =&gt; 10000
  </code></pre>
  
  <p>I assumed this would work but no such luck, anyone have some pointers?</p>
  
  <p>Thanks!</p>