Fix #126: Update link to Anki decks (#206)

README.md

@@ -50,9 +50,9 @@ Additional topics for interview prep:
 
 The provided [Anki flashcard decks](https://apps.ankiweb.net/) use spaced repetition to help you retain key system design concepts.
 
-* [System design deck](resources/flash_cards/System%20Design.apkg)
-* [System design exercises deck](resources/flash_cards/System%20Design%20Exercises.apkg)
-* [Object oriented design exercises deck](resources/flash_cards/OO%20Design.apkg)
+* [System design deck](https://github.com/donnemartin/system-design-primer/tree/master/resources/flash_cards/System%20Design.apkg)
+* [System design exercises deck](https://github.com/donnemartin/system-design-primer/tree/master/resources/flash_cards/System%20Design%20Exercises.apkg)
+* [Object oriented design exercises deck](https://github.com/donnemartin/system-design-primer/tree/master/resources/flash_cards/OO%20Design.apkg)
 
 Great for use while on-the-go.