motion/adapters/array_finder_query.rb
def create(options)
      raise ArgumentError.new("Creating on a relation requires the parent be saved first.") if @related_object.nil?
      obj = new(options)
      obj.save
      obj
    end
def create(options)
      raise ArgumentError.new("Creating on a relation requires the parent be saved first.") if @related_object.nil?
      obj = new(options)
      obj.save
      obj
    end
relation support 
 task.assignees.create(:name => 'bob')
 creates a new Assignee object on the Task object task