Update organization name to 'rails'

CONTRIBUTING.md

@@ -5,7 +5,7 @@
 Clone the repository from GitHub.
 
 ```
-$ git clone https://github.com/sstephenson/execjs
+$ git clone https://github.com/rails/execjs
 ```
 
 Now just cd into the directory and run `bundle install` to install the

MAINTAINING.md

@@ -9,7 +9,7 @@ version "2.x.x" bump is in order.
 ### Make a release commit
 
 To prepare the release commit, edit the
-[lib/execjs/version.rb](https://github.com/sstephenson/execjs/blob/master/lib/execjs/version.rb)
+[lib/execjs/version.rb](https://github.com/rails/execjs/blob/master/lib/execjs/version.rb)
 `VERSION` value. Then make a single commit with the description as
 "ExecJS 2.x.x". Finally, tag the commit with `v2.x.x`.
 

execjs.gemspec

@@ -5,7 +5,7 @@ Gem::Specification.new do |s|
   s.name    = "execjs"
   s.version = ExecJS::VERSION
 
-  s.homepage    = "https://github.com/sstephenson/execjs"
+  s.homepage    = "https://github.com/rails/execjs"
   s.summary     = "Run JavaScript code from Ruby"
   s.description = "ExecJS lets you run JavaScript code from Ruby."
 

lib/execjs/runtimes.rb

@@ -43,7 +43,7 @@ module ExecJS
     def self.autodetect
       from_environment || best_available ||
         raise(RuntimeUnavailable, "Could not find a JavaScript runtime. " +
-          "See https://github.com/sstephenson/execjs for a list of available runtimes.")
+          "See https://github.com/rails/execjs for a list of available runtimes.")
     end
 
     def self.best_available