voucher_code: description must be present
voucher_code: user must be given
cleanup
voucher create: add route to create a voucher
voucher create: render voucher creation page
voucher create: ensure user is logged in
voucher save: add route for saving a new voucher
voucher save: ensure user is logged in
voucher create: assigns a new voucher code instance
voucher show: add route to show a single voucher