private async void createBtn_Click(object sender, RoutedEventArgs e)
        {
            if (usernameTextBox.Text == "" || emailTextBox.Text == "" || passwordTextBox.Password == "" || confirmPasswordTextBox.Password == "")
            {
                MessageBox.Show("Username, Email and Password are required.");
            }
            else
            {
                RegisterBinder registerBinder = new RegisterBinder()
                {
                    Email           = emailTextBox.Text,
                    FName           = firstNameTextBox.Text,
                    LName           = lastNameTextBox.Text,
                    PhoneNumber     = phoneNumberTextBox.Text,
                    Username        = usernameTextBox.Text,
                    Password        = passwordTextBox.Password,
                    ConfirmPassword = confirmPasswordTextBox.Password,
                };

                await userManager.Register(registerBinder);

                if (userManager.Register(registerBinder) == null)
                {
                    mainWindow.GoToThingPage();
                }
            }
        }
        /// <summary>
        ///     Register account
        /// </summary>
        /// <param name="binder"></param>
        /// <returns>Error strings, null if OK</returns>
        public string[] Register(RegisterBinder binder)
        {
            string[] result;
            using (var client = CreateWebClient())
            {
                try
                {
                    client.UploadString(Uri + "/Register", JsonConvert.SerializeObject(binder));

                    HandleCookies(client.ResponseHeaders);

                    result = null;
                }
                catch (WebException e)
                {
                    result = ErrorResponse.Handle(e).Errors.ToArray();
                }
            }

            return(result);
        }