Force files to be precompiled by the Rails 3 asset pipeline via instructions in _precompile.js and _precompile.css. Add this to config/environments/production.rb

precompile_assets.rb

  get_requires_from_file = Proc.new do |filename| 
    files = Sprockets::DirectiveProcessor.new(filename).directives.collect { |f| f[1] == "require" ? f[2] : nil }.compact
    files.collect do |file|
      search_path = File.join(File.dirname(filename), file)
      files = Dir.glob("#{search_path}.*")
      files.collect { |f| File.basename(f) }
    end.flatten
  end
  config.assets.precompile +=
    get_requires_from_file.call("app/assets/javascripts/_precompile.js") +
    get_requires_from_file.call("app/assets/stylesheets/_precompile.css")