add cocoapod podspec

ReactUdp.podspec

@@ -0,0 +1,24 @@
+Pod::Spec.new do |s|
+  s.name                = 'ReactUdp'
+  s.version             = '0.1.0'
+  s.summary             = 'node\'s dgram API in React Native.'
+  s.description         = <<-DESC
+                            Enables accessing udp sockets in React Native.
+                         DESC
+  s.homepage            = 'https://github.com/tradle/react-native-udp'
+  s.license             = { :type => 'MIT' }
+  s.authors             = { 'Mark Vayngrib' => 'mark.vayngrib@lablz.com' }
+  s.source              = { :git => 'https://github.com/tradle/react-native-udp.git' }
+  s.default_subspec     = 'Core'
+  s.requires_arc        = true
+  s.platform            = :ios, '7.0'
+  s.prepare_command     = 'npm install --production'
+  s.preserve_paths      = 'node_modules', '**/*.js', 'package.json'
+  s.header_mappings_dir = '.'
+  s.dependency 'React'
+
+  s.subspec 'Core' do |ss|
+    ss.source_files     = '*.{c,h,m}', 'CocoaAsyncSocket/*.{h,m}'
+    ss.preserve_paths   = '*.js'
+  end
+end