fixed bug in dbgatway where id -1 was getting added to database

Author: lucasprates74

src/data/FlashcardSets.csv

@@ -1,3 +1,4 @@
 title,description,isPrivate,flashcardSetId,ownerUsername,flashcardIds
-test set 1,for testing study use case,true,0,testUser,0,1,2,3
+test set 1,for testing study use case,false,0,testUser,0,1,2,3
 empty test set,for testing study use case with empty set,true,1,testUser
+new test set,new set for testing flashcards,false,2,testUser