ios: add podspec file

Supersedes react-native-webrtc#136

Documentation/iOSInstallation.md

@@ -16,6 +16,15 @@
 
 ![Picture 4](https://github.com/oney/react-native-webrtc/blob/master/Documentation/doc_install_xcode_file_structure.png)
 
+## iOS Podfile
+
+You can use the included podspec in your podfile to take care of all dependencies instead of manually adding files to the project (instead of steps 2 through 5, but you might still have to do step 6 above).
+
+Include in a Podfile in your react-native ios directory:
+
+```
+pod 'react-native-webrtc', :path => '../node_modules/react-native-webrtc'
+```
 
 ## 2. Add Library Search Path
 

react-native-webrtc.podspec

@@ -0,0 +1,23 @@
+require 'json'
+
+package = JSON.parse(File.read(File.join(__dir__, 'package.json')))
+
+Pod::Spec.new do |s|
+  s.name                = package['name']
+  s.version             = package['version']
+  s.summary             = package['description']
+  s.homepage            = 'https://github.com/oney/react-native-webrtc'
+  s.license             = package['license']
+  s.author              = 'https://github.com/oney/react-native-webrtc/graphs/contributors'
+  s.source              = { :git => 'git@github.com:oney/react-native-webrtc.git', :tag => 'release #{s.version}' }
+  s.requires_arc        = true
+
+  s.platform            = :ios, '9.0'
+
+  s.preserve_paths      = 'ios/**/*'
+  s.source_files        = 'ios/**/*.{h,m}'
+  s.libraries           = 'c', 'sqlite3', 'stdc++'
+  s.framework           = 'AudioToolbox','AVFoundation', 'CoreAudio', 'CoreGraphics', 'CoreVideo', 'GLKit', 'VideoToolbox'
+  s.ios.vendored_frameworks = 'ios/WebRTC.framework'
+  s.xcconfig            = { 'OTHER_LDFLAGS' => '-framework WebRTC' }
+end