Update guides intro.

Author: beauby

source/guides/index.html.md

@@ -3,11 +3,32 @@ layout: guides
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 # Introduction
 
-jsonapi-rb is a ruby library for producing and consuming
-[JSON API](http://jsonapi.org) documents. It has tight integrations with various
-frameworks ([Ruby on Rails](http://rubyonrails.org) and
-[Hanami](http://hanamirb.org) at the moment), but it is not tied to any of
-those.
+## What is jsonapi-rb?
+[jsonapi-rb](https://github.com/jsonapi-rb/jsonapi-rb) is a ruby library for
+producing and consuming [JSON API](http://jsonapi.org) documents. It is cleanly
+layered, has an intuitive yet intention-stating API, and no magic.
+
+It is comprised of 4 independent micro-libraries:
+
++ [jsonapi-parser](https://github.com/jsonapi-rb/parser) for syntactic
+validation of JSON API documents,
++ [jsonapi-renderer](https://github.com/jsonapi-rb/renderer) for low-level
+rendering of JSON API documents,
++ [jsonapi-serializable](https://github.com/jsonapi-rb/serializable) for
+building serializable resource classes from your business object,
++ [jsonapi-deserializable](https://github.com/jsonapi-rb/deserializable) for
+building deserializable resource classes that transform an incoming JSON API
+payload into a custom hash,
+
+and 2 framework integrations:
++ [jsonapi-rails](https://github.com/jsonapi-rb/rails) for
+[Ruby on Rails](http://rubyonrails.org), with ActionController integration and
+generators,
++ [jsonapi-hanami](https://github.com/jsonapi-rb/hanami) for
+[Hanami](http://hanamirb.org) with Hanami::Controller::Action integration and
+(soon) generators.
+
+## Guides
 
 These guides should get you up to speed with using jsonapi-rb. If you have more
 questions, feel free to drop by on [Gitter](http://gitter.im/jsonapi-rb).