rendering.md in active_model_serializers-0.10.3

- old
+ new

@@ -80,12 +80,16 @@
 
 See [Fields](fields.md) for more information.
 
 #### adapter
 
-PR please :)
+This option lets you explicitly set the adapter to be used by passing a registered adapter. Your options are `:attributes`, `:json`, and `:json_api`.
 
+```
+ActiveModel::Serializer.config.adapter = :json_api
+```
+
 #### key_transform
 
 ```render json: posts, each_serializer: PostSerializer, key_transform: :camel_lower```
 
 See [Key Transforms](key_transforms.md) for more information.
@@ -236,9 +240,39 @@
       "title": "how to do open source"
     }
   }
 ```
 Note: the `Attributes` adapter (default) does not include a resource root. You also will not be able to create a single top-level root if you are using the :json_api adapter.
+
+#### namespace
+
+The namespace for serializer lookup is based on the controller.
+
+To configure the implicit namespace, in your controller, create a before filter
+
+```ruby
+before_action do
+  self.namespace_for_serializer = Api::V2
+end
+```
+
+`namespace` can also be passed in as a render option:
+
+
+```ruby
+@post = Post.first
+render json: @post, namespace: Api::V2
+```
+
+This tells the serializer lookup to check for the existence of `Api::V2::PostSerializer`, and if any relations are rendered with `@post`, they will also utilize the `Api::V2` namespace.  
+
+The `namespace` can be any object whose namespace can be represented by string interpolation (i.e. by calling to_s)
+- Module `Api::V2`
+- String `'Api::V2'`
+- Symbol `:'Api::V2'`
+
+Note that by using a string and symbol, Ruby will assume the namespace is defined at the top level.
+
 
 #### serializer
 
 PR please :)
 