Adde route method to builder for single route.

Removed state () from Router

src/axum/app.rs

@@ -42,6 +42,11 @@ impl AppBuilder {
         Self::default()
     }
 
+    pub fn route(mut self, route: Router) -> Self {
+        self.router = self.router.merge(route);
+        self
+    }
+
     pub fn routes(mut self, routes: impl IntoIterator<Item = Router>) -> Self {
         self.router = routes.into_iter().fold(self.router, Router::merge);
         self

src/axum/router.rs

@@ -21,7 +21,7 @@
 #[cfg(feature = "axum")]
 macro_rules! router {
     ($body:expr) => {
-        pub(crate) fn router() -> axum::Router<()> {
+        pub(crate) fn router() -> axum::Router {
             $body
         }
     };
@@ -104,6 +104,6 @@ mod tests {
 
     #[test]
     fn test_join_routes() {
-        let _router: Router<()> = join_routes![Router::new(), Router::new()];
+        let _router: Router = join_routes![Router::new(), Router::new()];
     }
 }