README.md in alba-1.1.0 vs README.md in alba-1.2.0

@@ -57,22 +57,18 @@
 
 You can find the documentation on [RubyDoc](https://rubydoc.info/github/okuramasafumi/alba).
 
 ## Features
 
-* Resource-based serialization
-* Arbitrary attribute definition
-* One and many association with the ability to define them inline
-* Adding condition and filter to association
-* Parameters can be injected and used in attributes and associations
 * Conditional attributes and associations
 * Selectable backend
 * Key transformation
 * Root key inference
 * Error handling
 * Resource name inflection based on association name
 * Circular associations control
+* Types for validation and conversion
 * No runtime dependencies
 
 ## Anti features
 
 * Sorting keys
@@ -246,11 +242,11 @@
 RestrictedFooResouce.new(foo).serialize
 # => '{"name":"my foo"}'
 end
 ```
 
-### Attribute key transformation
+### Key transformation
 
 ** Note: You need to install `active_support` gem to use `transform_keys` DSL.
 
 With `active_support` installed, you can transform attribute keys.
 
@@ -276,10 +272,43 @@
 user = User.new(1, 'Masafumi', 'Okura')
 UserResourceCamel.new(user).serialize
 # => '{"id":1,"firstName":"Masafumi","lastName":"Okura"}'
 ```
 
+You can also transform root key when:
+
+* `Alba.enable_inference!` is called
+* `key!` is called in Resource class
+* `root` option of `transform_keys` is set to true or `Alba.enable_root_key_transformation!` is called.
+
+```ruby
+Alba.enable_inference!
+
+class BankAccount
+  attr_reader :account_number
+
+  def initialize(account_number)
+    @account_number = account_number
+  end
+end
+
+class BankAccountResource
+  include Alba::Resource
+
+  key!
+
+  attributes :account_number
+  transform_keys :dash, root: true
+end
+
+bank_account = BankAccount.new(123_456_789)
+BankAccountResource.new(bank_account).serialize
+# => '{"bank-account":{"account-number":123456789}}'
+```
+
+This behavior to transform root key will become default at version 2.
+
 Supported transformation types are :camel, :lower_camel and :dash.
 
 ### Filtering attributes
 
 You can filter attributes by overriding `Alba::Resource#converter` method, but it's a bit tricky.
@@ -454,9 +483,48 @@
 ### Circular associations control
 
 You can control circular associations with `within` option. `within` option is a nested Hash such as `{book: {authors: books}}`. In this example, Alba serializes a book's authors' books. This means you can reference `BookResource` from `AuthorResource` and vice versa. This is really powerful when you have a complex data structure and serialize certain parts of it.
 
 For more details, please refer to [test code](https://github.com/okuramasafumi/alba/blob/master/test/usecases/circular_association_test.rb)
+
+### Types
+
+You can validate and convert input with types.
+
+```ruby
+class User
+  attr_reader :id, :name, :age, :bio, :admin, :created_at
+
+  def initialize(id, name, age, bio = '', admin = false) # rubocop:disable Style/OptionalBooleanParameter
+    @id = id
+    @name = name
+    @age = age
+    @admin = admin
+    @bio = bio
+    @created_at = Time.new(2020, 10, 10)
+  end
+end
+
+class UserResource
+  include Alba::Resource
+
+  attributes :name, id: [String, true], age: [Integer, true], bio: String, admin: [:Boolean, true], created_at: [String, ->(object) { object.strftime('%F') }]
+end
+
+user = User.new(1, 'Masafumi OKURA', '32', 'Ruby dev')
+UserResource.new(user).serialize
+# => '{"name":"Masafumi OKURA","id":"1","age":32,"bio":"Ruby dev","admin":false,"created_at":"2020-10-10"}'
+```
+
+Notice that `id` and `created_at` are converted to String and `age` is converted to Integer.
+
+If type is not correct and auto conversion is disabled (default), `TypeError` occurs.
+
+```ruby
+user = User.new(1, 'Masafumi OKURA', '32', nil) # bio is nil and auto conversion is disabled for bio
+UserResource.new(user).serialize
+# => TypeError, 'Attribute bio is expected to be String but actually nil.'
+```
 
 ### Caching
 
 Currently, Alba doesn't support caching, primarily due to the behavior of `ActiveRecord::Relation`'s cache. See [the issue](https://github.com/rails/rails/issues/41784).