make appeals editable

app/policies/post_appeal_policy.rb

@@ -1,5 +1,17 @@
 class PostAppealPolicy < ApplicationPolicy
-  def permitted_attributes
+  def edit?
+    update?
+  end
+
+  def update?
+    unbanned? && record.pending? && record.creator_id == user.id
+  end
+
+  def permitted_attributes_for_create
     [:post_id, :reason]
   end
+
+  def permitted_attributes_for_update
+    [:reason]
+  end
 end