Dynamically uploading a list that's already in a form

In my app I simply have a submit_to_remote within the larger form...
no need for a nested form. It submits the entire form including the
other fields but I only read the category[:name] param when I receive
it in my CategoriesController#create action.

Inside a larger form...
  <%= text_field_tag 'category[name]' %>
  <%= submit_to_remote 'add_category', 'Add', :url => categories_path

I belive there is a :submit parameter available for submit_to_remote
that should specify which field(s) to submit instead of the whole
form, but I haven't played with that. (See the API doc for
link_to_remote: as I understand it, submit_to_remote uses the same