root_to method?

I would like to move source/index.html.erb into a directory to sit nicely alongside the partials I’m using in index.html.erb.

Is there an existing way to move the source/index.html.erb into a directory?

Something like

# config.rb
root_to 'root#index'

So that I can do

source/
  root/
   |- _hero_box.html.erb
   |- index.html.erb

And where would css, js and images folder reside? source is the root of the HTML, moving it around would make it unintuitive if other assets folders would still be on source.