code: private void addConstructorParameter(final MethodSpec.Builder constructorBuilder, final String attributeName, final TypeName type) {
          constructorBuilder.addParameter(type, attributeName, Modifier.FINAL);
          constructorBuilder.addCode("this." + attributeName + "=" + attributeName + ";");
      }
docs: adds attribute to constructor
  @param constructorBuilder constructor to modify
  @param attributeName name of attribute to be added
  @param type type of attribute to be added