Anyone here know how to do a proper IIS URL Rewrite to go from folder to sub domain?

[JEFF MACK]

I need to go from this url:
http://www.brickpicker.com/forum/index.php/topic/11266-whsmith-daily-mail-lego-promotion-giveaway-20th-september-27th-september/

to this new subdomain url while removing the index.php part.

http://community.brickpicker.com/topic/11266-whsmith-daily-mail-lego-promotion-giveaway-20th-september-27th-september/

I have been working with this so far but its not removing the index.php

<rule name="forum redirect" stopProcessing="true">
	<match url="^forum/index.php/(.*)$" ignoreCase="false" />
	<action type="Redirect" redirectType="Permanent" url="http://community.brickpicker.com/{R:1}" />
</rule>