Installing Ruby on Rails 4 on Mac

For installing Rails 4, you must install or upgrade your Ruby version.

The Ruby must be higher then 1.9.3, read more

In this section i'm using Ruby 2.0

Step 1: Installing Ruby 2.0

I think you must install XCode firstly, after installed the XCode GCC was included,
it's make easy when installing Ruby.
To install Ruby here's have two ways:

• Installing Ruby with Macports
• Installing Ruby with RVM

Step 2: Installing Rails

sudo gem install rails