有机会再试一试Rails了，只是原来接触的是2，现在已然变成了4，似乎现在的安装比原来会快些。。
Rails 4 安装
针对于安装了RVM
gem install rails
没有的话应该这样：
sudo gem install rails
安装RVM可以用句
curl -L https://get.rvm.io | bash -s stable
查看rails版本
rails -v
Rails 4.0.3
似乎这就是当前的最新版本
Ruby版本
We recommend Ruby 2.1.0 for use with Rails. We stopped supporting Ruby 1.8.x after Rails 3.2. Ruby 1.9.2+ will be supported until Rails 5.
官方推荐用2.1.0. 也就是最新版本
安装SQLite
似乎这就是诸如Django、Rails这类对于轻量级网站的数据库要求。
如果是mac os
brew install sqlite3
其他可以看情况安装，如openSUSE
sudo zypper install sqlite3
Rails 4 Hello,World
可以直接用rails生成
$rails new hello
于是就有了
create
create README.rdoc
create Rakefile
create config.ru
create .gitignore
create Gemfile
create app
create app/assets/javascripts/application.js
create app/assets/stylesheets/application.css
create app/controllers/application_controller.rb
create app/helpers/application_helper.rb
create app/views/layouts/application.html.erb
create app/assets/images/.keep
create app/mailers/.keep
create app/models/.keep
create app/controllers/concerns/.keep
create app/models/concerns/.keep
create bin
create bin/bundle
create bin/rails
create bin/rake
create config
create config/routes.rb
create config/application.rb
create config/environment.rb
create config/environments
create config/environments/development.rb
create config/environments/production.rb
create config/environments/test.rb
create config/initializers
create config/initializers/backtrace_silencers.rb
create config/initializers/filter_parameter_logging.rb
create config/initializers/inflections.rb
create config/initializers/mime_types.rb
create config/initializers/secret_token.rb
create config/initializers/session_store.rb
create config/initializers/wrap_parameters.rb
create config/locales
create config/locales/en.yml
create config/boot.rb
create config/database.yml
create db
create db/seeds.rb
create lib
