issue #97: new structure: route grouping

Signed-off-by: horea <horea@rospace.com>

Author: Howriq

docs/book/v6/extended-features/route-grouping.md

@@ -0,0 +1,28 @@
+# Route grouping
+
+In Dotkernel 6.0 with the help of the new [dot-router](https://docs.dotkernel.org/dot-router/v1/overview/) package, we have managed to implement a nicer way of creating routes.
+A lot of the times developers need to create sets of routes that have a similar format. As an example:
+
+```php
+$app->post('/product/create', CreateProductHandler::class, 'product:create');
+$app->delete('/product/delete/{id}', DeleteProductHandler::class, 'product:delete');
+$app->patch('/product/update/{id}', UpdateProductHandler::class, 'product:update');
+$app->get('/product/view/{id}', GetProductHandler::class, 'product:view');
+```
+
+Along with the features from `mezzio/mezzio-fastroute`, the new `dot-router` package provides the ability to create route groups which are collections of routes that have the same base string for the path.
+
+Here we have an example from `src/User/src/RoutesDelegator.php` with the new grouping method:
+
+```php
+$routeCollector->group('/user/' . $uuid)
+    ->delete('', DeleteUserResourceHandler::class, 'user::delete-user')
+    ->get('', GetUserResourceHandler::class, 'user::view-user')
+    ->patch('', PatchUserResourceHandler::class, 'user::update-user');
+```
+
+The advantages of this new implementation:
+- DRY - no need for repeating common route parts
+- encapsulation - similar routes are grouped in a single block of code (vs each route a separate statement)
+- easy path refactoring - modify all routes at once by changing only the prefix
+- easy copying/moving - copying/moving an entire group makes sure that you don't accidentally omit a route