Add RubyGems metadata and require MFA to release this gem

Author: rafaelfranca

activeresource.gemspec

@@ -4,9 +4,10 @@ $LOAD_PATH.push File.expand_path("../lib", __FILE__)
 require "active_resource/version"
 
 Gem::Specification.new do |s|
+  version = ActiveResource::VERSION::STRING
   s.platform    = Gem::Platform::RUBY
   s.name        = "activeresource"
-  s.version     = ActiveResource::VERSION::STRING
+  s.version     = version
   s.summary     = "REST modeling framework (part of Rails)."
   s.description = "REST on Rails. Wrap your RESTful web app with Ruby classes and work with them like Active Record models."
   s.license     = "MIT"
@@ -15,6 +16,14 @@ Gem::Specification.new do |s|
   s.email       = "[email protected]"
   s.homepage    = "http://www.rubyonrails.org"
 
+  s.metadata = {
+    "bug_tracker_uri"   => "https://github.com/rails/activeresource/issues",
+    "changelog_uri"     => "https://github.com/rails/activeresource/releases/tag/v#{version}",
+    "documentation_uri" => "http://rubydoc.info/gems/activeresource",
+    "source_code_uri"   => "https://github.com/rails/activeresource/tree/v#{version}",
+    "rubygems_mfa_required" => "true",
+  }
+
   s.files = Dir["MIT-LICENSE", "README.md", "lib/**/*"]
   s.require_path = "lib"