osx 編譯安裝配置 ruby on rails

1. 下載源代碼：

   curl -O http://cache.ruby-lang.org/pub/ruby/2.2/ruby-2.2.2.tar.gz

2. 解壓：

   tar xf ruby-2.2.2.tar.gz

3. 編譯：

   cd ruby-2.2.2
   
   ./configure --prefix=/opt/local/ --program-suffix=22
   
   make
   
   sudo make install

4. 安裝 rails:

   sudo gem22 install rails -- --with-extension-lib=/opt/local/lib --with-opt-dir=/opt/local

5. 測試：

   rails new hello
   
   cd hello
   
   rails server