pundit: convert wiki pages to pundit.

app/policies/wiki_page_policy.rb

@@ -0,0 +1,17 @@
+class WikiPagePolicy < ApplicationPolicy
+  def update?
+    unbanned? && (can_edit_locked? || !record.is_locked?)
+  end
+
+  def revert?
+    update?
+  end
+
+  def can_edit_locked?
+    user.is_builder?
+  end
+
+  def permitted_attributes
+    [:title, :body, :other_names, :other_names_string, :is_deleted, (:is_locked if can_edit_locked?)].compact
+  end
+end