add .podspec file for installation via CocoaPods

react-native-signature-capture.podspec

@@ -0,0 +1,16 @@
+require "json"
+
+package = JSON.parse(File.read(File.join(__dir__, "package.json")))
+
+Pod::Spec.new do |s|
+  s.name         = "react-native-signature-capture"
+  s.version      = package["version"]
+  s.summary      = package["description"]
+  s.author       = package["author"]
+  s.homepage     = package["homepage"]
+  s.license      = package["license"]
+  s.platform     = :ios, "8.4"
+  s.source       = { :git => "https://github.com/RepairShopr/react-native-signature-capture", :tag => "#{s.version}" }
+  s.source_files  = "ios/*.{h,m}"
+  s.dependency "React"
+end