Don't broadcast updates of cards unless published

To prevent https://fizzy.37signals.com/5986089/cards/1631

app/controllers/cards_controller.rb

@@ -27,7 +27,9 @@ class CardsController < ApplicationController
   end
 
   def update
-    @card.update! card_params
+    suppressing_broadcasts_unless_published(@card) do
+      @card.update! card_params
+    end
 
     if @card.published?
       render_card_replacement
@@ -50,6 +52,14 @@ class CardsController < ApplicationController
       @card = Current.user.accessible_cards.find params[:id]
     end
 
+    def suppressing_broadcasts_unless_published(&block)
+      if @card.published?
+        yield
+      else
+        Collection.suppressing_turbo_broadcasts(&block)
+      end
+    end
+
     def card_params
       params.expect(card: [ :status, :title, :description, :image, tag_ids: [] ])
     end