Pro ASP.Net MVC 5 Platform - Ch 13 - Added UserValidator to Create

Used the out of the box user validator. Configured it to only allow
alphanumeric characters for the user name and does not allow duplicates for
the email address.
Pro ASP.Net MVC 5 Platform - Ch 13 - Added CustomUserValidator to Create

Created a custom user validator just to show how easy it is to make one. This
one blocks anyone who's email domain is not @example.com.