plataformatec/simple_form — pull request #382 by semaperepelitsa (2011-12-05 20:31:19+00:00)
Title: Grouped collection input

I wanted to add grouped collection input so that you could do `f.association :category, :collection => Category.roots, :group_method => :children`. Rails has `grouped_collection_select` alongside with `collection_select` so it should be pretty similar to existing collection input.

The only thing I don't know how to deal with is how SimpleForm maps inputs to classes. Right now every input with collection option maps to select input type which maps to CollectionInput. I wish every input with group_method option map to the same select input type but also somehow map it to GroupedCollectionInput.

Do you like my idea and do you have any suggestions on the problem? Thanks.