print message to System.err because we want to see them on `systemctl status hacky`

src/main/java/linux/general/hackyquizbot/QuizBackend.java

@@ -16,7 +16,7 @@ public class QuizBackend {
 	
 	static {
 		try (Connection connection = DriverManager.getConnection(dbName, dbUsername, dbPassword)) {
-		    System.out.println("Database connected!");
+		    System.err.println("Database connected!");
 		}
 		catch (SQLException e) {
 			System.err.println("Could not connect to DB.");