Create new Rails app with gemset, using postgresql

rails_new

$ rvm use --create 2.1@app_name
$ gem install rails --no-ri --no-rdoc
$ rails new app_name --database=postgresql
$ cd app_name/
$ rvm --rvmrc 2.1@app_name
$ git init
$ git add .

# setup db
$ rake db:drop db:create db:migrate db:seed

# other setup
$ rails generate rspec:install
$ rails generate devise:install
$ rails generate devise User