Add support of adding optional "secret" phrase to sign up rules so users having identical email domain could get different roles like JohnDoe@domain.com with "ninja" secret gets admin account and JamesDarrel@domain.com with "summer" secret gets only author one.
Feature: SignUpRules
Add support of adding optional "secret" phrase to sign up rules so users having identical email domain could get different roles like JohnDoe@domain.com with "ninja" secret gets admin account and JamesDarrel@domain.com with "summer" secret gets only author one.