ADded ordering to documentation

docs/docs/guides/input/ordering.md

@@ -0,0 +1,51 @@
+# Ordering
+
+If you want to allow the user to order your querysets by a number of different attributes, you can use the provided class `OrderingSchema`. `OrderingSchema`, as a regular `Schema`, it uses all the
+necessary features from Pydantic, and adds some some bells and whistles that will help use transform it into the usual Django queryset ordering.
+
+You can start using it, importing the `OrderingSchema` and using it in your API handler in conjunction with `Query`:
+
+```python hl_lines="4"
+from ninja import OrderingSchema
+
+@api.get("/books")
+def list_books(request, ordering: OrderingSchema = Query(...)):
+    books = Book.objects.all()
+    books = ordering.sort(books)
+    return books
+```
+
+Just like described in [defining query params using schema](./query-params.md#using-schema), Django Ninja converts the fields defined in `OrderingSchema` into query parameters. In this case, the field is only one: `order_by`. This field will accept multiple string values.
+
+You can use a shorthand one-liner `.sort()` to apply the ordering to your queryset:
+
+```python hl_lines="4"
+@api.get("/books")
+def list_books(request, ordering: OrderingSchema = Query(...)):
+    books = Book.objects.all()
+    books = ordering.sort(books)
+    return books
+```
+
+Under the hood, `OrderingSchema` expose a query parameter `order_by` that can be used to order the queryset. The `order_by` parameter expects a list of string, representing the list of field names that will be passed to the `queryset.order_by(*args)` call. This values can be optionally prefixed by a minus sign (`-`) to indicate descending order, following the same standard from Django ORM.
+
+## Restricting Fields
+
+By default, `OrderingSchema` will allow to pass any field name to order the queryset. If you want to restrict the fields that can be used to order the queryset, you can use the `allowed_fields` field in the `OrderingSchema.Config` class definition:
+
+```python hl_lines="3"
+class BookOrderingSchema(OrderingSchema):
+    class Config(OrderingSchema.Config):
+        allowed_fields = ['name', 'created_at']  # Leaving out `author` field
+```
+
+This class definition will restrict the fields that can be used to order the queryset to only `name` and `created_at` fields. If the user tries to pass any other field, a `ValidationError` will be raised.
+
+## Default Ordering
+
+If you want to provide a default ordering to your queryset, you can assign a default value in the `order_by` field in the `OrderingSchema` class definition:
+
+```python hl_lines="2"
+class BookOrderingSchema(OrderingSchema):
+    order_by: List[str] = ['name']
+```

docs/mkdocs.yml

@@ -59,6 +59,7 @@ nav:
           - guides/input/file-params.md
           - guides/input/request-parsers.md
           - guides/input/filtering.md
+          - guides/input/ordering.md
       - Handling responses:
           - Defining a Schema: guides/response/index.md
           - guides/response/temporal_response.md