private void AssignPermissionsForm_Load(object sender, EventArgs e)
        {
            List <OperationVO> userOperations = manager.GetOperationsOfUser(selectedUser);
            List <OperationVO> all            = manager.GetAll();

            textBox1.Text = selectedUser.Username;

            for (int i = 0; i < all.Count; i++)
            {
                checkedListBox1.Items.Add(all[i]);

                if (userOperations.Contains(all[i]))
                {
                    checkedListBox1.SetItemChecked(i, true);
                }
                else
                {
                    checkedListBox1.SetItemChecked(i, false);
                }
            }
        }