Assets have a separate Thumbnail

[calumgunn]

Hey, all.

This has arisen on a couple of projects, but it's more pressing on an upcoming one, so after some chatting with Mathew, Jamie and Tom, there's a movement to add a 'thumbnail' to an Asset.

The use case of this is where you would like the thumbnail of an image to be beyond the scope of what Paperclip can do, compositionally.

The first commit I've pushed here adds a has_one to Asset - a recursive relationship, as seen here: http://www.rubydoc.info/github/mongoid/mongoid/master/Mongoid%2FRelations%2FCyclic%2FClassMethods%3Arecursively_embeds_one (I didn't use the recursively_embeds_one helper, because the resulting child_asset method is a bit undesirable).

Wanted to put this out to all y'all and get this one moving, as the aforementioned project is looming.

Work yet to do:

• Add UI for adding a Thumbnail to an existing Asset

[jgwhite]

Interesting approach. In theory, both could appear side by side in the asset library but visually "linked" somehow.

For the Heart use case, I wonder if we could introduce a filenaming convention that automatically establishes these relationships.

i.e. if you prepare you folder of images like this:

my-cool-image.jpg
my-cool-image-thumb.jpg
my-cat-biscuits.jpg
my-cat-biscuits-thumb.jpg

and chuck them into Slices, then it will automatically setup the -thumbs with their parents.