Feature Request: Add Custom Fields

I’ve looked at the docs and I’m not sure if this is possible, but it would be really good if you could add the ability to add custom fields rather than just the default

Name
Address
Email Address
Phone
Subject
Message

I appreciate this is a free plugin and I am very grateful for it as I use it in a few sites I host.

Thanks

http://ww.wp.xz.cn/extend/plugins/contact-form-plugin/