Missing first: true element causes failure #14
Description
If a collection does not have a first: true, item, that collection cannot be viewed, even if a siblings method has been defined. An error is raised:
Multiple or no first items in the list where found. Consider defining a siblings method
To fix this you have to first add first: true to an item, then call all.each(&:prepend).
This is a problem, for example when resort is added to an existing data set. Is there a way to set a default behavior in this case?