pundit: convert notes to pundit.

app/policies/note_policy.rb

@@ -0,0 +1,13 @@
+class NotePolicy < ApplicationPolicy
+  def revert?
+    update?
+  end
+
+  def permitted_attributes_for_create
+    [:x, :y, :width, :height, :body, :post_id, :html_id]
+  end
+
+  def permitted_attributes_for_update
+    [:x, :y, :width, :height, :body]
+  end
+end