Allows for custom rules to be defined. Custom rules MUST define a method and errorMessage in the rule config

pat_email: {
    rules: {
        custom: {
            error: "I just don't like you",
            method: function(val){
                if(val == 'someoneIhate@crappydomain.com'){
                    return false;
                }
            }
        }
    }
}