fix test compile

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

@@ -143,5 +143,11 @@ public class StubDatabaseDao implements IDatabaseDao {
 		// TODO Auto-generated method stub
 		return 0;
 	}
+	
+	@Override
+	public List<Session> getMySessions(String username) {
+		// TODO Auto-generated method stub
+		return null;
+	}
 
 }