void Authorization::on_pushButton_login_clicked()
{
    QString username = ui->lineEdit_username->text();
    QString password = ui->lineEdit_password->text();

    connectionIsOpened();
    QSqlQuery query;
    query.prepare("SELECT 1 FROM users WHERE username=:username AND password=:password");
    query.bindValue(":username", username);
    query.bindValue(":password", QString(QCryptographicHash::hash(password.toUtf8(), QCryptographicHash::Md5).toHex()));
    if ( query.exec() )
    {
        int cnt = 0;

        while ( query.next() ) {
            cnt++;
        }

        if (cnt == 1)
        {

            connectionIsClosed();
            this->hide();
            Analisys an;
            an.setModal(true);
            an.exec();
        }

        else if (cnt < 1)
        {
            QMessageBox::warning(this, "Error", "Login or password is not correct");
            return;
        }
    }

}