upgrade to rails4 configuration.

I used ruby 2.0.0 and rails 4.0.x, and I needed to make website using devise/cancan. But the environment of this repo had ruby 1.9.x and rails 3.2.x so I tried to upgrade configurations. 

1. remove old configurations and  add new configurations

2. reinstall devise because some of configurations is changed according to update version 3.2.2
- If not necessary, modify it please. 

3. modify that 'name' property doesn't set when I try to sign in and modify my account. 
- please see the file below
https://github.com/joohee/rails3-bootstrap-devise-cancan/blob/80a54f0c60f76facf22bcc293f01c91549115131/app/controllers/application_controller.rb

I hope that this is so meaningful to you guyz. :+1: