john.wallace PRO said over 1 year ago on Saving Attributes with Hotwire :
Nice Video.

I think in AutoSaveBuilder instead of: 
  # def select(attribute, options = {})
  #   merge_data_controller(options)
  #   super(attribute, options)
  # end

It should be this 
  # def select(method, choices = nil, options = {}, html_options = {}, &block)  
  #   merge_data_controller(html_options)  
  #   super(method, choices, options, html_options, &block)  
  # end

Also, there are a few other places where html_options would be passed to merge_data_controller rather than options, for it to work though I have only tried select so far.