README.md in alba-0.8.0 vs README.md in alba-0.9.0

@@ -23,10 +23,28 @@
 
     $ gem install alba
 
 ## Usage
 
+### Configuration
+
+Alba's configuration is fairly simple.
+
+#### Backend
+
+Backend is the actual part serializing an object into JSON. Alba supports these backends.
+
+* Oj, the fastest. Gem installation required.
+* active_support, mostly for Rails. Gem installation required.
+* default or json, with no external dependencies.
+
+You can set a backend like this:
+
+```ruby
+Alba.backend = :oj
+```
+
 ### Simple serialization with key
 
 ```ruby
 class User
   attr_accessor :id, :name, :email, :created_at, :updated_at
@@ -123,15 +141,53 @@
 # => '{"foo":{"id":1,"articles":[{"title":"Hello World!","body":"Hello World!!!"},{"title":"Super nice","body":"Really nice!"}]}}'
 ```
 
 Although this might be useful sometimes, it's generally recommended to define a class for both Resource and Serializer.
 
+### Inheritance and Ignorance
+
+You can `exclude` or `ignore` certain attributes using `ignoring`.
+
+```ruby
+class Foo
+  attr_accessor :id, :name, :body
+
+  def initialize(id, name, body)
+    @id = id
+    @name = name
+    @body = body
+  end
+end
+
+class GenericFooResource
+  include Alba::Resource
+
+  attributes :id, :name, :body
+end
+
+class RestrictedFooResouce < GenericFooResource
+  ignoring :id, :body
+end
+
+RestrictedFooResouce.new(foo).serialize
+# => '{"name":"my foo"}'
+end
+```
+
 ## Comparison
 
 Alba is faster than alternatives.
 For a performance benchmark, see https://gist.github.com/okuramasafumi/4e375525bd3a28e4ca812d2a3b3e5829.
 
+## Rails
+
+When you use Alba in Rails, you can create an initializer file with the line below for compatibility with Rails JSON encoder.
+
+```ruby
+Alba.backend = :active_support
+```
+
 ## Why named "Alba"?
 
 The name "Alba" comes from "albatross", a kind of birds. In Japanese, this bird is called "Aho-dori", which means "stupid bird". I find it funny because in fact albatrosses fly really fast. I hope Alba looks stupid but in fact it does its job quick.
 
 ## Alba internals
@@ -140,10 +196,10 @@
 
 `Serializer` is a component responsible for rendering JSON output with `Resource`. `Serializer` can add more data to `Resource` such as `metadata`. Users can define one single `Serializer` and reuse it for all `Resource`s. The main interface is `#serialize`.
 
 `Resource` is a component responsible for defining how an object (or a collection of objects) is converted into JSON. The difference between `Serializer` and `Resource` is that while `Serializer` can add arbitrary data into JSON, `Resource` can get data only from the object under it. The main interface is `#serializable_hash`.
 
-`Value` is either `Attribute`, `One` or `Many`. They are responsible for fetching data from the object for `Resource`. The main interface is `#to_hash`.
+`One` and `Many` are the special object fetching other resources and converting them into Hash.
 
 The main `Alba` module holds config values and one convenience method, `.serialize`.
 
 ## Development