UserSettingsController.confirm_email.ex

def confirm_email(conn, %{"token" => token}) do
  case Accounts.update_user_email(conn.assigns.current_user, token) do
    :ok ->
      conn
      |> put_flash(:info, "Email changed successfully.")
      |> redirect(to: Routes.user_settings_path(conn, :edit))

    :error ->
      conn
      |> put_flash(:error, "Email change link is invalid or it has expired.")
      |> redirect(to: Routes.user_settings_path(conn, :edit))
  end
end