add more documentation to pagination links

Author: bacarini

README.md

@@ -274,9 +274,9 @@ The `url` declaration describes which named routes to use while generating URLs
 for your JSON. Not every adapter will require URLs.
 ## Pagination
 
-Pagination links will be included in your response automatically as long as the resource is paginated using [Kaminari](https://github.com/amatsuda/kaminari) or [WillPaginate](https://github.com/mislav/will_paginate) and if you are using a ```JSON-API``` adapter. The others adapters does not have this feature.
+Pagination links will be included in your response automatically as long as the resource is paginated using [Kaminari](https://github.com/amatsuda/kaminari) or [WillPaginate](https://github.com/mislav/will_paginate) and if you are using a ```JSON-API``` adapter.
 
-For more information about it, please see in our docs [How to add pagination links](https://github.com/rails-api/active_model_serializers/blob/master/docs/howto/add_pagination_links.md)
+Although the others adapters does not have this feature, it is possible to implement pagination links to `JSON` adapter. For more information about it, please see in our docs [How to add pagination links](https://github.com/rails-api/active_model_serializers/blob/master/docs/howto/add_pagination_links.md)
 
 ## Caching
 

docs/README.md

@@ -12,7 +12,7 @@ This is the documentation of AMS, it's focused on the **0.10.x version.**
 ## How to
 
 - [How to add root key](howto/add_root_key.md)
-- [How to add pagination links](howto/add_pagination_links.md) (```JSON-API``` only)
+- [How to add pagination links](howto/add_pagination_links.md)
 
 ## Getting Help
 

docs/howto/add_pagination_links.md

@@ -1,6 +1,8 @@
 # How to add pagination links
 
-Pagination links will be included in your response automatically as long as the resource is paginated and if you are using a ```JSON-API``` adapter. The others adapters does not have this feature.
+### JSON-API adapter
+
+Pagination links will be included in your response automatically as long as the resource is paginated and if you are using a ```JSON-API``` adapter.
 
 If you want pagination links in your response, use [Kaminari](https://github.com/amatsuda/kaminari) or [WillPaginate](https://github.com/mislav/will_paginate).
 
@@ -44,3 +46,53 @@ ex:
 ```
 
 AMS relies on either [Kaminari](https://github.com/amatsuda/kaminari) or [WillPaginate](https://github.com/mislav/will_paginate). Please install either dependency by adding one of those to your Gemfile.
+
+### JSON adapter
+
+If you are using `JSON` adapter, pagination links will not be included automatically, but it is possible to do so using `meta` key.
+
+In your action specify a custom serializer.
+```ruby
+render json: @posts, serializer: PaginatedSerializer, each_serializer: PostPreviewSerializer
+```
+
+And then, you could do something like the following class.
+```ruby
+class PaginatedSerializer < ActiveModel::Serializer::ArraySerializer
+  def initialize(object, options={})
+    meta_key = options[:meta_key] || :meta
+    options[meta_key] ||= {}
+    options[meta_key] = {
+      current_page: object.current_page,
+      next_page: object.next_page,
+      prev_page: object.prev_page,
+      total_pages: object.total_pages,
+      total_count: object.total_count
+    }
+    super(object, options)
+  end
+end
+```
+ex.
+```json
+{
+  "articles": [
+    {
+      "id": 2,
+      "title": "JSON API paints my bikeshed!",
+      "body": "The shortest article. Ever."
+    }
+  ],
+  "meta": {
+    "current_page": 3,
+    "next_page": 4,
+    "prev_page": 2,
+    "total_pages": 10,
+    "total_count": 10
+  }
+}
+```
+
+### FlattenJSON adapter
+
+This adapter does not allow us to use `meta` key, due to that it is not possible to add pagination links.