Feature request #1348: Optional "name" field for anonymous commenters

As commented in issue #1268, it would be nice if anonymous visitors could at least tag their posts with a "name" without opening an account. I guess the same applies to issue tracker tickets.

At the moment all such models have an "owner", which consists of a user_id. Basically, if a logged-in user "owns" the post the that will be reflected in the user_id and if the post is anonymous then the user_id will be nil.

I guess what would be needed is a new name column (will have to check if that is a reserved keyword in either Rails or MySQL) that could be optionally populated for records with user_id of nil. Could even had an email column so that anonymous users could provide a way of getting back in touch with them. Don't think I'll ever add a homepage or URL column, as I think a lot of comment spam uses precisely that to get links published.

As far as validation is concerned, I think it would be fairly loose: basically the same as for the display_name field for real users: letters, numbers, and a must be unique (at least at the time of posting).