Use clean_url helper.

lib/gollum/app.rb

@@ -279,7 +279,7 @@ module Precious
         # Renaming preserves format, so add the page's format to the renamed path to retrieve the renamed page
         new_path = "#{rename}.#{Gollum::Page.format_to_ext(page.format)}"
         # Add a redirect from the old page to the new
-        wiki.add_redirect(page.url_path, new_path.gsub(/(^\/)/, '')) if @redirects_enabled
+        wiki.add_redirect(page.url_path, clean_url(new_path)) if @redirects_enabled
 
         page = wiki_page(new_path).page
         return if page.nil?

lib/gollum/helpers.rb

@@ -17,7 +17,7 @@ module Precious
 
     # Remove all slashes from the start of string.
     # Remove all double slashes
-    def clean_url url
+    def clean_url(url)
       return url if url.nil?
       url.gsub('%2F', '/').gsub(/^\/+/, '').gsub('//', '/')
     end