private void button1_Click(object sender, EventArgs e)
        {
            ADDstudent f2 = new ADDstudent();

            f2.Show();
            //this.Hide();

            this.Visible = false;
            //signin.ActiveForm
        }
        private void button2_Click_1(object sender, EventArgs e)
        {
            userType = "Tutor";
            ADDstudent f2 = new ADDstudent();

            f2.Show();
            //this.Hide();

            this.Visible = false;
            //signin.ActiveForm
        }