Use ascending list for serializing where possible.

src/Text/Hakyll/Page.hs

@@ -149,5 +149,5 @@ instance Renderable Page where
 
 -- Make pages serializable.
 instance Binary Page where
-    put (Page context) = put $ M.toList context
-    get = liftM (Page . M.fromList) get
+    put (Page context) = put $ M.toAscList context
+    get = liftM (Page . M.fromAscList) get

src/Text/Hakyll/Tags.hs

@@ -45,9 +45,9 @@ readTagMap :: String -- ^ Unique identifier for the tagmap.
            -> Hakyll (M.Map String [FilePath])
 readTagMap identifier paths = do
     isCacheMoreRecent' <- isCacheMoreRecent fileName paths
-    if isCacheMoreRecent' then M.fromList <$> getFromCache fileName
+    if isCacheMoreRecent' then M.fromAscList <$> getFromCache fileName
                           else do tagMap <- readTagMap'
-                                  storeInCache (M.toList tagMap) fileName
+                                  storeInCache (M.toAscList tagMap) fileName
                                   return tagMap
   where
     fileName = "_tagmap" </> identifier