lib/redis-model-extension/validation.rb
def valid_item_for_redis_key? args, key
      (args.has_key?(key) && !args[key].nil?) || redis_fields_config[key] == :autoincrement
    end
def valid_item_for_redis_key? args, key
      (args.has_key?(key) && !args[key].nil?) || redis_fields_config[key] == :autoincrement
    end
validate one item of redis key