README.md in bright_serializer-0.1.1 vs README.md in bright_serializer-0.2.0

@@ -1,6 +1,7 @@
 [![Actions Status](https://github.com/petalmd/bright_serializer/workflows/Build/badge.svg)](https://github.com/petalmd/bright_serializer/actions?query=workflow%3ABuild)
+[![Gem Version](https://badge.fury.io/rb/bright_serializer.svg)](https://badge.fury.io/rb/bright_serializer)
 
 # BrightSerializer
 
 This is a very light and fast gem to serialize object in a Ruby project.
 
@@ -117,9 +118,30 @@
 class AccountSerializer
   include BrightSerializer::Serializer
   attributes :id, :first_name, :last_name
   
   attribute :friends do |object|
+    FriendSerializer.new(object.friends)
+  end
+end
+```
+
+### Entity
+
+You can define the entity of your serializer to generate documentation with the option `entity`.
+The feature was build to work with [grape-swagger](https://github.com/ruby-grape/grape-swagger). 
+For more information about defining a model entity see the [Swagger documentation](https://swagger.io/specification/v2/?sbsearch=array%20response#schema-object).
+
+```ruby
+class AccountSerializer
+  include BrightSerializer::Serializer
+  attribute :id, entity: { type: :string, description: 'The id of the account' }
+  attribute :name
+
+  attribute :friends,
+    entity: { 
+      type: :array, items: { ref: 'FriendSerializer' }, description: 'The list the account friends.'
+     } do |object|
     FriendSerializer.new(object.friends)
   end
 end
 ```