Add Carthage info to README

Author: Anthony Weiss

README.md

@@ -20,7 +20,9 @@ TransitionKit is a small Cocoa library that provides an API for implementing a s
 * Thorougly unit tested. You know it works and can make changes with confidence.
 * Lightweight. TransitionKit has no dependencies beyond the Foundation library and works on iOS and Mac OS X.
 
-## Installation via CocoaPods
+## Installation 
+
+### Via CocoaPods
 
 The recommended approach for installing TransitionKit is via the [CocoaPods](http://cocoapods.org/) package manager, as it provides flexible dependency management and dead simple installation. For best results, it is recommended that you install via CocoaPods **>= 0.16.0** using Git **>= 1.8.0** installed via Homebrew.
 
@@ -54,6 +56,16 @@ Open your project in Xcode from the .xcworkspace file (not the usual project fil
 $ open MyProject.xcworkspace
 ```
 
+### Via Carthage
+
+Instructions for using Carthage can be found [here](https://github.com/Carthage/Carthage).
+
+Add the following to your Cartfile:
+
+```
+github "blakewatters/TransitionKit"
+```
+
 ## Examples
 
 #### Simple Example