def set key, value
      # capture new value in instance
      send("#{key}=", value)
      attributes.merge!(key => value)
      # and store it
      File.write UserConfig.config_path, YAML.dump(attributes)
    end
def set key, value
      # capture new value in instance
      send("#{key}=", value)
      attributes.merge!(key => value)
      # and store it
      File.write UserConfig.config_path, YAML.dump(attributes)
    end
Public: Set and store a new configuration value