http://rakeroutes.com/blog/rvm-workflow-for-a-new-rails-app/
Creating a new Rails app
# create and use the new RVM gemset
$ rvm use --create 1.9.3@awesome_rails_project
# install rails into the blank gemset
$ gem install rails
# generate the new rails project
$ rails new awesome_rails_project
# go into the new project directory and create an .rvmrc for the gemset
$ cd awesome_rails_project
$ rvm --rvmrc 1.9.3@awesome_rails_project
# verify the rvmrc
$ cd ..; cd -