private void RegisterButton_Click(object sender, EventArgs e)
        {
            String username = UsernameBox.Text;
            String password = PasswordBox.Text;

            try
            {
                Employee employee = ctrl.RegisterEmployee(username, password);
                if (employee == null)
                {
                    this.Hide();
                    loginForm.Show();
                    this.Close();
                }
                else
                {
                    MessageBox.Show("Date Invalide ! ");
                }
            }
            catch (SqliteException er)
            {
                MessageBox.Show("Exista deja un utilizator cu acest username ! ");
                UsernameBox.Text = "";
                PasswordBox.Text = "";
            }
        }