fix the page naming lambda, add demo

closes #18

reploy.hs

@@ -190,8 +190,9 @@ pageName' :: Site (FilePath -> String)
 pageName' = do
   ps <- use pages
   pure $ \mnt' ->
-    just ("template looks for undefined page name : " ++ mnt')
-      $  ps M.!? unAbsolute mnt' >>= (^? pageMeta . key "template" . _String . to T.unpack)
+    just ("lookup for undefined page name : " ++ mnt')
+      $ ps M.!? unAbsolute mnt'
+          >>= (^? pageMeta . key "name" . _String . to T.unpack)
 
 -- | Like `Mu.substitute` but writes (and eventually should throw) stuff on errors
 checkedSubstitute :: Mu.Template -> MT.Value -> IO T.Text

templates/header.html

@@ -1,9 +1,10 @@
 <header>
   Navigation:
   <ul>
+    <li><a href="{{#pageLink}}/{{/pageLink}}">{{#pageName}}/{{/pageName}}</a></li>
     <li><a href="{{#pageLink}}/tag{{/pageLink}}">Tags</a></li>
     <li><a href="{{#pageLink}}/list{{/pageLink}}">List</a></li>
-    <li><a href="{{#pageLink}}/search{{/pageLink}}">Search</a></li>
+    <li><a href="{{#pageLink}}/search{{/pageLink}}">{{#pageName}}/search{{/pageName}}</a></li>
   </ul>
 
   {{?htags}}