nebirhos/activeadmin-sortable-tree — pull request #20 by zorab47 (2013-11-18 14:45:44+00:00)
Title: Add option to specify :roots_collection proc

Allow users to define custom logic to find the roots of the tree to be rendered, while staying backward compatible.

### Example

```ruby
ActiveAdmin.register TreeNode do
sortable tree: true,
roots_collection: proc { current_user.tree_nodes.roots }
end
```