Add link to the carthage demo

Author: serejahh

README.md

@@ -109,6 +109,8 @@ To install manually the KolodaView class in an app, just drag the KolodaView, Dr
     ```
 5. `KolodaView` works with default implementation. Override it to customize its behavior
 
+Also check out [an example project with carthage](https://github.com/serejahh/Koloda-Carthage-usage).
+
 Properties
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