finish router refrence

docs/router/src/reference/static-generation.md

@@ -0,0 +1,15 @@
+# Static Generation
+
+## Getting the Sitemap
+
+The [`Routable`] trait includes an associated [`SITE_MAP`] constant that contains the map of all of the routes in the enum.
+
+By default, the sitemap is a tree of (static or dynamic) RouteTypes, but it can be flattened into a list of individual routes with the `.flatten()` method.
+
+## Generating a Sitemap
+
+To statically render pages, we need to flatten the route tree and generate a file for each route that contains only static segments:
+
+```rust, no_run
+{{#include ../../../../packages/router/examples/static_generation.rs}}
+```