Edit message property in messages list

I'm writing a web-based organizer of email messages.

Let's say I have boolean “Marked as Important” property for each message. I display it with an icon in the list of messages (for each message in list). And I want to give user ability to change this property by clicking this icon right to particular message in the messages list, just like the “Starred” icon in Gmail.

I'm a newbie in RoR, so my suggestion is to add some action in the messages controller (“mark_as_important”, for example) and try to make it work almost like Update action: it should inverse boolean “Marked as Important” property of message, update it and redirect back to messages list (I don't want to use AJAX for the first time, may be I'll add it later).

How can I do this? Do I really need to add specific action in the controller or I can use Update action (in this case, what code should I place there?)?