Update README.md

README.md

@@ -35,6 +35,17 @@ main() async {
 }
 ```
 
+# Push State Example
+```dart
+var vDir = new VirtualDirectory(...);
+var indexFile = new File.fromUri(vDir.source.uri.resolve('index.html'));
+
+app.after.add((req, ResponseContext res) {
+  // Fallback to index.html on 404
+  return res.sendFile(indexFile);
+});
+```
+
 # Options
 The `VirtualDirectory` API accepts a few named parameters:
 - **source**: A `Directory` containing the files to be served. If left null, then Angel will serve either from `web` (in development) or
@@ -46,4 +57,4 @@ The `VirtualDirectory` API accepts a few named parameters:
 - **debug**: Print verbose debug output.
 - **callback**: Runs before sending a file to a client. Use this to set headers, etc. If it returns anything other than `null` or `true`,
 then the callback's result will be sent to the user, instead of the file contents.
-- **streamToIO**: If set to `true`, files will be streamed to `res.io`, instead of added to `res.buffer`.. Default is `false`.
+- **streamToIO**: If set to `true`, files will be streamed to `res.io`, instead of added to `res.buffer`.. Default is `false`.