Use page_route() for custom.css, custom.js, and MathJax

lib/gollum/templates/layout.mustache

@@ -8,7 +8,7 @@
   {{#sprockets_stylesheet_tag}}app{{/sprockets_stylesheet_tag}}
   {{#sprockets_stylesheet_tag}}print print{{/sprockets_stylesheet_tag}}
 
-  {{#css}}<link rel="stylesheet" type="text/css" href="{{custom_path}}/custom.css" media="all">{{/css}}
+  {{#css}}<link rel="stylesheet" type="text/css" href="{{custom_css}}" media="all">{{/css}}
   {{#noindex}}<meta name="robots" content="noindex, nofollow" />{{/noindex}}
 
 
@@ -49,11 +49,11 @@
     };
   </script>
   {{#mathjax_config}}
-  <script type="text/javascript" src="{{base_url}}/{{mathjax_config}}"></script>
+  <script type="text/javascript" src="{{mathjax_config}}"></script>
   {{/mathjax_config}}
-  <script defer src="{{base_url}}/gollum/assets/mathjax/MathJax.js?config=TeX-AMS-MML_HTMLorMML"></script>
+  <script defer src="{{mathjax_js}}"></script>
   {{/mathjax}}
-  {{#js}}<script type="text/javascript" src="{{custom_path}}/custom.js"></script>{{/js}}
+  {{#js}}<script type="text/javascript" src="{{custom_js}}"></script>{{/js}}
 
   <title>{{title}}</title>
 </head>

lib/gollum/views/layout.rb

@@ -26,12 +26,24 @@ module Precious
         !@path.nil?
       end
 
-      def base_url
+      def custom_path
         @base_url
       end
 
-      def custom_path
-        "#{@base_url}"
+      def custom_css
+        clean_url(custom_path, "custom.css")
+      end
+
+      def custom_js
+        clean_url(custom_path, "custom.js")
+      end
+
+      def mathjax_config
+        page_route(@mathjax_config)
+      end
+
+      def mathjax_js
+        page_route("gollum/assets/mathjax/MathJax.js?config=TeX-AMS-MML_HTMLorMML")
       end
 
       def css # custom css