install nodejs 0.6.2 and railwayjs on ubuntu

过程略碰上点小麻烦，存档如下：
1.append source:

  sudo apt-get install python-software-properties
sudo add-apt-repository ppa:chris-lea/node.js
sudo apt-get update
sudo apt-get install nodejs

2. install latest npm and nodejs

sudo apt-get install npm nodejs

3. install railwayjs

npm install railway -g