organized js assets

completes #11

app/helpers/application_helper.rb

@@ -28,4 +28,14 @@ module ApplicationHelper
                          %w(Coder live_code)
                        ], selected: (val.blank? ? '' : val))
   end
+
+  # include javascript only once
+  # Allows the safe loading of js dependencies in partials multiple times.
+  def content_for_javascript_once code_label, &block
+    @js_blocks ||= []
+    return if @js_blocks.include? code_label
+
+    @js_blocks << code_label
+    content_for :custom_javascipt, &block
+  end
 end