updated readme

Author: Bastian Bartmann

README.md

@@ -12,6 +12,14 @@ And then execute:
 
     $ bundle
 
+Add this line to `app/assets/javascripts/application.js`:
+
+    //= require podlove-web-player-rails
+
+And add this line to `app/assets/stylesheets/application.css.scss`:
+
+    //= @import "podlove-web-player";
+
 ## Usage
 
 TODO: Write usage instructions here