[Radiant] Conflicting updates

[Daniel Sheppard]

Just had my first instance of conflicting updates - I edited a page while somebody else was editing it too without realising it -
luckily in this instance we were both trying to do the same thing, but this could lead to data loss without warning.

Time for some big red flashing warning lights.

I'm going to add a hidden field to the Page editing page containing the last updated value of the page - that will be sent back to
the server and the validation should check that the updated_at field in the database matches - if not, a bit red error saying
something like

"This page has been modified since you last loaded it. The last user to edit this page was <username of culprit>. If you continue
saving this page their changes may be lost". 

There will then by a checkbox with that option saying something like 'ignore <usernames>'s changes and save my changes anyway'
allowing you to continue with your save if that's what is appropriate - that will set a second field that will tell the object to
ignore that validation. I'm not 100% sure of doing this - you could always copy/paste and just do it again, but I think this way is
probably nicer.

Anybody have any objections to handling conflicts in this way? Or better ideas (that DON'T involve writing making a version control
system for pages)? I'll probably check in a change tomorrow if there isn't any.

Dan.