Looks like it already does it... So I dont need to do anything more than remove that prop.

        class GitHubSerializerStrategy : PocoJsonSerializerStrategy
        {
            protected override string MapClrMemberNameToJsonFieldName(string clrPropertyName)
            {
                return clrPropertyName.ToRubyCase();
            }

Which points to: 

        public static string ToRubyCase(this string propertyName)
        {
            Ensure.ArgumentNotNullOrEmptyString(propertyName, "s");
            return string.Join("_", propertyName.SplitUpperCase()).ToLowerInvariant();
        }