Also the client should validate this field and report problems first, so we need to:
1) fix the regex
2) add help_test explaining the expected format
3) add more information about expected format to server side error message
4) validate on the client side
5) provide clear client side error messages for any failures on the client side, as per 3
Also the client should validate this field and report problems first, so we need to:
1) fix the regex
2) add help_test explaining the expected format
3) add more information about expected format to server side error message
4) validate on the client side
5) provide clear client side error messages for any failures on the client side, as per 3