README.md in shiyo-0.1.0 vs README.md in shiyo-0.1.1

@@ -1,14 +1,16 @@
 # Shiyo
 [![johnny-miyake](https://circleci.com/gh/johnny-miyake/shiyo.svg?style=svg)](https://github.com/johnny-miyake/shiyo)
 
-Shiyo is a minimal framework that supports writing your business rules using the Specification pattern.
-It enables to build composite specifications by method chaining like;
+Shiyo is a minimal framework that supports writing your business rules using the [Specification pattern](https://en.wikipedia.org/wiki/Specification_pattern).
+It helps you to build a composite specification by method chaining like;
 ```ruby
 spec1.and(spec2.or(spec3)).satisfied_by?(candidate)
 ```
 
+[API documentation](https://www.rubydoc.info/gems/shiyo)
+
 ## Installation
 
 Add this line to your application's Gemfile:
 
 ```ruby
@@ -22,10 +24,15 @@
 Or install it yourself as:
 
     $ gem install shiyo
 
 ## Usage
+You can create your own Shiyo specification as following steps;
+1. Include `Shiyo::Specification` module into your class.
+2. Implement `#satisfied_by?`.
+3. (optional) Implement `#initialize` if needed.
 
+For example;
 ```ruby
 # A specification class
 class ContainerFeatureSpec
   include Shiyo::Specification