Collections: nesting insert behavior

[mark-dce]

Basically, moved collections should be inserted immediately after the drop target and before any successive images in the collection.

1. Newly created curated collections should be added as the first item in the root list i.e. they should show up at the top of the 'Course Collections' or 'My Collections' pane
   root.members = [new_collection] + root.members
2. Curated collections dragged immediately below a higher level collection should be placed first in that containing collection parent_collection.members = [moved_collection] + parent_collection.members

3. Curated collections dragged after another sub collection at the same level should be inserted immediately after the target sibling parent_collection.members = parent_collection.members.insert_after(target_sibling, moved_collection) (#2 might just be handled as a special case of this where there is no preceding sibling)

1. Curated collections dragged out of a collection should be deleted from their origination collection. The order of other items in the original collection should be maintained.

[mark-dce]

@jcoyne - let me know if you think there are any cases I missed here - I think the rules really cover everything.

[jcoyne]

How about reordering subcollections within a parent collection?

old: a - b1
       \ b2

new: a - b2
       \ b1

How about when adding, removing and reordering:

old: a - b1
       \ b2
       \ b3

new: a - b4
       \ b3
       \ b5
       \ b1