Update README.md

README.md

@@ -70,12 +70,17 @@ $ brew update
 $ brew install carthage
 ```
 
-To integrate Format into your Xcode project using Carthage, specify it in your `Cartfile`:
+To integrate Zip into your Xcode project using Carthage, specify it in your `Cartfile`:
 
 ```ogdl
 github "marmelroy/Zip"
 ```
 
+When installing make sure to use submodules: 
+```bash
+carthage update --use-submodules
+```
+
 ### Setting up with [CocoaPods](http://cocoapods.org/?q=Zip)
 ```ruby
 source 'https://github.com/CocoaPods/Specs.git'