README.md in rbdock-0.1.1 vs README.md in rbdock-0.1.2

@@ -6,27 +6,18 @@
 
 Dockerfile to prepare ruby is almost common, so generate its common parts. This is still experimetal and under heavy construction.
 
 ## Installation
 
-Add this line to your application's Gemfile:
+```bash
+$ gem install rbdock
+```
 
-    gem 'rbdock'
-
-And then execute:
-
-    $ bundle
-
-Or install it yourself as:
-
-    $ gem install rbdock
-
-
 ## Usage
 
 ### Create Dockerfile to build ruby
 
-Create `Dockerfile` to build ruby 2.0.0-p353 ready image.
+Create `Dockerfile` to build ruby 2.1.0 ready image.
 
 ```
 $ rbdock 2.1.0
 ```