Changes to database chapter

Author: iseppala

_posts/2016-08-11-build-maintainable-systems-with-hexagonal-architecture.md

@@ -89,8 +89,10 @@ The methods in LotteryNotificationsImpl adapter are simple System.out printers s
 
 The last secondary port is the database. It contains methods for storing and retrieving lottery tickets.
 
-<script src="http://gist-it.appspot.com/http://github.com/iluwatar/java-design-patterns/raw/master/hexagonal/src/main/java/com/iluwatar/hexagonal/database/LotteryTicketRepository.java?slice=23:"></script>
-<script src="http://gist-it.appspot.com/http://github.com/iluwatar/java-design-patterns/raw/master/hexagonal/src/main/java/com/iluwatar/hexagonal/database/LotteryTicketInMemoryRepository.java?slice=23:"></script>
+<script src="http://gist-it.appspot.com/http://github.com/iluwatar/java-design-patterns/raw/master/hexagonal/src/main/java/com/iluwatar/hexagonal/database/LotteryTicketRepository.java?slice=30:"></script>
+<script src="http://gist-it.appspot.com/http://github.com/iluwatar/java-design-patterns/raw/master/hexagonal/src/main/java/com/iluwatar/hexagonal/database/LotteryTicketInMemoryRepository.java?slice=31:"></script>
+
+The LotteryTicketInMemoryRepository is a mock database holding its contents in memory only. We use Optionals to indicate whether the operation was successful or not.
 
 ## Lottery application