Add skelet functions to StubDatabaseDao

src/test/java/de/thm/arsnova/dao/StubDatabaseDao.java

@@ -574,6 +574,18 @@ public class StubDatabaseDao implements IDatabaseDao {
 		stats.setInterposedQuestions(0);
 		return stats;
 	}
+	
+	@Override
+	public List<String> getSubjects(Session session, String questionVariant) {
+		// TODO Auto-generated method stub
+		return null;
+	}
+	
+	@Override
+	public List<String> getQuestionIdsBySubject(Session session, String questionVariant, String subject) {
+		// TODO Auto-generated method stub
+		return null;
+	}
     
     @Override
     public SortOrder createOrUpdateSortOrder(SortOrder sortOrder) {
@@ -586,4 +598,3 @@ public class StubDatabaseDao implements IDatabaseDao {
 		// TODO Auto-generated method stub
 		return null;
 	}
-}