title: Ruby on Rails: How to migrate changes after adding validation on models?
body: <p>I'm new to Ruby on Rails and I'm currently working on models. I have added a new validation to pre created attribute.</p>
  <p>This is the validation that I have added.</p>
  <pre><code>validates_presence_of :services, :message =&gt; 'This field is non-editable'
  </code></pre>
  <p>Do I have to migrate the changes after adding validation? If yes then how?</p>
  <p>Any kind of help would be greatly appreciated.</p>