Add PromiseKit dependency

- Added PromiseKit dependency

Carthage/Checkouts/PromiseKit/Extensions/StoreKit/Sources/SKRequest+AnyPromise.h

@@ -0,0 +1,31 @@
+//
+//  PromiseKit+StoreKit.h
+//  Aluxoft SCP
+//
+//  Created by Josejulio Martínez on 16/05/14.
+
+#import <PromiseKit/AnyPromise.h>
+#import <StoreKit/SKRequest.h>
+
+/**
+ To import the `SKRequest` category:
+
+    use_frameworks!
+    pod "PromiseKit/StoreKit"
+ 
+ And then in your sources:
+ 
+    @import PromiseKit;
+*/
+@interface SKRequest (PromiseKit)
+
+/**
+ Sends the request to the Apple App Store.
+
+ @return A promise that fulfills when the request succeeds. If the
+ receiver is an SKProductsRequest, the promise fulfills with its
+ `SKProductsResponse`, otherwise the promise is void.
+*/
+- (AnyPromise *)promise NS_REFINED_FOR_SWIFT;
+
+@end