Improve README (close #17)

Readme.md

@@ -1,16 +1,15 @@
 Rails 3.1 asset-pipeline gem to provide underscore.js
 
-# Install
-
-	gem 'underscore-rails'
+# Setup
 
+Have in your Gemfile:
 
-# Use
+	gem 'underscore-rails'
 
-In your application.js manifest:
+And, have in your application.js manifest:
 
 	//= require underscore
 
-or directly available under `/assets/underscore.js`
+(also directly available under `/assets/underscore.js`)
 
-Easy as pie.
+Easy as pie.