private static void addUsers(Connection connection, int count, int minLength, int maxLength) throws SQLException {
        Statement statement = connection.createStatement();

        usersIDList = new ArrayList<Integer>(count);

        for (int index = 0; index < count; index++) {
            final String username = RandomStringUtils.randomAlphabetic(new Random().nextInt(maxLength - minLength) + minLength) + index;
            final String password = RandomStringUtils.randomAlphabetic(20);
            final String info = RandomStringUtils.randomAlphabetic(20);
            final String pathpic = RandomStringUtils.randomAlphabetic(20);
            statement.executeUpdate(String.format("INSERT INTO users (login, password, info, path_pic) VALUES (\'%s\',\'%s\',\'%s\',\'%s\');", username, password, info, pathpic));
            ResultSet res = statement.executeQuery("SELECT lastval();");
            res.next();
            int userID = res.getInt(1);
            usersIDList.add(userID);
        }

        statement.close();
    }

    private static void addSubscriptions(Connection connection, int minCount, int maxCount) throws SQLException {
        Statement statement = connection.createStatement();

        for (int id : usersIDList) {
            final int count = new Random().nextInt(maxCount - minCount) + minCount + 1;
            for (int i = 0; i < count; i++) {
                if (id == usersIDList.get(i)) {
                    continue;
                }
                statement.executeUpdate(String.format("INSERT INTO subscriptions (subscriber_id, to_user_id) VALUES (%d, %d);", id, usersIDList.get(i)));
            }
        }

        statement.close();
    }