Iframes not allowed in redactor?

[zachrnolan]

I'm not able to embed iframes in the editor, how can I get this to work?

1. Paste iframe into editor

   <iframe src="https://embed.spotify.com/?uri=spotify%3Atrack%3A6Gre6x4ZyBg5xSRPywGIHL" width="300" height="380" frameborder="0" allowtransparency="true"></iframe>

2. Save

3. After save, redactor changes iframe code to this:

   <iframe src="https://embed.spotify.com/?uri=spotify%3Atrack%3A6Gre6x4ZyBg5xSRPywGIHL" width="300" height="380" frameborder="0" allowtransparency="true"></iframe>