Get the stable version of rvm:
$ rvm get stable
Install Ruby 2.0
$ rvm install ruby-2.0.0
Create a Gemset;
$ rvm gemset create rails-4.0
Goto that gemset:
$ rvm use ruby-2.0.0-p247@rails-4.0
Install Rails 4.0
$ gem install rails --version=4.0
Create an rvmrc file in root folder:
$ vim rvmrc $ rvm --rvmrc use ruby-2.0.0-p247@rails-4.0
uncomment the line gem ‘therubyracer’, platforms: :ruby from Gemfile
Start the server:
$ rails s
You are ready to go!!
Changes that you may need to perform while working with Rails 4 compared to old versions:
1. Check here for the New changes in Rails 4
http://net.tutsplus.com/tutorials/ruby/digging-into-rails-4/
http://www.alfajango.com/blog/rails-4-whats-new/
http://www.sitepoint.com/get-your-app-ready-for-rails-4/
2. If you are using devise gem use devise version 3 or above (http://blog.plataformatec.com.br/2013/05/devise-and-rails-4/)