Fix small typo

Author: codeKonami

README.md

@@ -460,7 +460,7 @@ var RepoList = React.createClass({
 This demo is copied from [github.com/mhart/react-server-example](https://github.com/mhart/react-server-example), but I rewrote it with JSX syntax.
 
 ```bash
-# install the dependencies in demo12 directory
+# install the dependencies in demo13 directory
 $ npm install
 
 # translate all jsx file in src subdirectory to js file