expose router class (#127)

* Expose router_class for customization

docs/en/docs/release-notes.md

@@ -10,6 +10,9 @@ hide:
 ### Added
 
 - Add `ReceiveSendSniffer`. This sniffer allows to detect communication events and to replay receive messages.
+- `Include` and `BaseLilya` (application) have now a ClassVar `router_class` to provide a custom router.
+- Subclasses of `BaseLilya` (application) can set the `router_class` to None to provide a completely custom router
+  which initialization parameters aren't required to match the ones of `Router`.
 - Expose `fall_through` on `StaticFile`.
 
 ### Changed

lilya/apps.py

@@ -3,7 +3,7 @@
 import sys
 from collections.abc import Awaitable, Callable, Mapping, Sequence
 from functools import cached_property
-from typing import Annotated, Any, cast
+from typing import Annotated, Any, ClassVar, cast
 
 from lilya._internal._module_loading import import_string
 from lilya._utils import is_class_and_subclass
@@ -44,6 +44,9 @@
 
 
 class BaseLilya:
+    router_class: ClassVar[type[Router] | None] = Router
+    router: Router
+
     def __init__(
         self,
         debug: Annotated[bool, Doc("Enable or disable debug mode. Defaults to False.")] = False,
@@ -392,16 +395,17 @@ async def create_user(request: Request):
         self.state = State()
         self.middleware_stack: ASGIApp | None = None
 
-        self.router: Router = Router(
-            routes=routes,
-            redirect_slashes=redirect_slashes,
-            permissions=self.custom_permissions,
-            on_startup=on_startup,
-            on_shutdown=on_shutdown,
-            lifespan=lifespan,
-            include_in_schema=include_in_schema,
-            settings_module=self.settings,
-        )
+        if self.router_class is not None:
+            self.router = self.router_class(
+                routes=routes,
+                redirect_slashes=redirect_slashes,
+                permissions=self.custom_permissions,
+                on_startup=on_startup,
+                on_shutdown=on_shutdown,
+                lifespan=lifespan,
+                include_in_schema=include_in_schema,
+                settings_module=self.settings,
+            )
         self.__set_settings_app(self.settings, self)
 
     @property