add example for top links

t/example.t

@@ -58,6 +58,14 @@ $registry->add_type(
                 count => $xtra->{count},
                 total => 0+ @$data,
             }
+        },
+        top_level_links => {
+            self => '/articles',
+        },
+        links => {
+            self => sub($data,@) {
+                return "/articles/" . $data->{id};
+            },
         }
     }
 );
@@ -72,6 +80,9 @@ like $output => {
     "count"=> 2,
     "total"=> 1
   },
+  "links"=> {
+    "self"=> "/articles"
+  },
 };
 
 done_testing();