Update README.md
Found this tip about serving static files as a comment in a closed issue. I think it is valuable to have it explicitly defined in the README. Thanks.
diff --git a/README.md b/README.md
index 082e4cf..c5ac271 100644
--- a/README.md
+++ b/README.md
@@ -110,6 +110,13 @@
/src/subdir/somefile.go match
```
+### Static files
+You can replace the default NotFound handler in order to serve static files.
+```go
+// Serve static files from the ./public directory
+router.NotFound = http.FileServer(http.Dir("public")).ServeHTTP
+```
+
## How does it work?
The router relies on a tree structure which makes heavy use of *common prefixes*,
it is basically a *compact* [*prefix tree*](http://en.wikipedia.org/wiki/Trie)
