Provide etag for pins too

app/controllers/cards/pins_controller.rb

@@ -2,6 +2,7 @@ class Cards::PinsController < ApplicationController
   include CardScoped
 
   def show
+    fresh_when etag: @card.pin_for(Current.user) || "none"
   end
 
   def create

app/controllers/cards/watches_controller.rb

@@ -2,7 +2,7 @@ class Cards::WatchesController < ApplicationController
   include CardScoped
 
   def show
-    fresh_when etag: @card.watch_for(Current.user)
+    fresh_when etag: @card.watch_for(Current.user) || "none"
   end
 
   def create

app/models/card/pinnable.rb

@@ -9,6 +9,10 @@ module Card::Pinnable
     pins.exists?(user: user)
   end
 
+  def pin_for(user)
+    pins.find_by(user: user)
+  end
+
   def pin_by(user)
     pins.find_or_create_by!(user: user)
   end