Update README.md with installation via Carthage

Author: bcylin

README.md

@@ -1 +1,29 @@
-# ICInputAccessory
+# ICInputAccessory
+
+[![Carthage compatible](https://img.shields.io/badge/Carthage-compatible-4BC51D.svg?style=flat)](https://github.com/Carthage/Carthage)
+
+## Installation
+
+### Install via [Carthage](https://github.com/Carthage/Carthage)
+
+* Create a `Cartfile` with the following specification and run `carthage update`.
+
+  ```
+  github "polydice/ICInputAccessory"
+  ```
+
+* On your application targets' **General** settings tab, in the **Linked Frameworks and Libraries** section, drag and drop `ICInputAccessory.framework` from the Carthage/Build directory.
+
+* On your application targets’ **Build Phases** settings tab, click the **+** icon and choose **New Run Script Phase**. Create a Run Script with the following contents:
+
+  ```
+  /usr/local/bin/carthage copy-frameworks
+  ```
+
+  and add the following path to **Input Files**:
+
+  ```
+  $(SRCROOT)/Carthage/Build/iOS/ICInputAccessory.framework
+  ```
+
+* For more information, please check out the [Carthage Documentation](https://github.com/Carthage/Carthage#if-youre-building-for-ios).