Move things to trash

[jefflunt]

When you try to delete something, it should mark it as deleted (which hides it from the view, as opposed to actually deleting it), and allow you to restore it if you want.

The current thinking:

• The controls on the page have a "show trashed" button. When clicked, any items in the current section that were trashed are then revealed, and can be untrashed by a user with the appropriate permissions.
• Only Owners and Editors can view/trash/un-trash WorldObjects
• Only Owners can trash/untrash Sections and LogBooks

The "flash" message section at the top of the page should provide an "undo" link to undo the more recently trashed item.

The gem paranoia should take care of this. https://github.com/radar/paranoia - it automatically scopes all your queries (by default) to exclude "deleted_at" records.

[jefflunt]

So far so good, but there is a cascading issue. When an record is destroyed, the sub-records are also destroyed (or marked as deleted). What we want to do instead is just mark the parent object as deleted.

Also, the dependent: destroy relationships need to be lifted. This will probably handle the issue, actually.

[jefflunt]

Commit fed4c9d is actually related to this issue.

[jefflunt]

Deployed.