How to get Condition Group in Ransack?

I am using advanced search in Ransack which has default AND. I have made it as OR by putting .try(:merge, m: 'or'))

@search = Data.search(params[:q].try(:merge, m: 'or'))

but I am not able to get the AND/OR drop down as Condition Group like shown in Ransack Demo here http://ift.tt/1PM7QsC

How to do it as unfortunately Ransack wiki has no mention about it.