code: function (ravelInstance, resource, methodType, methodName) {
    let subpath = '';
    if (methodName === 'get' || methodName === 'put' || methodName === 'delete') {
      subpath = '/:id';
    }
  
    if (typeof resource[methodName] === 'function') {
      // use the mapping decorator to map the handler to correct path
      mapping(methodType, subpath)(
        Object.getPrototypeOf(resource),
        methodName,
        {
          value: resource[methodName].bind(resource)
        }
      );
    } else {
      // add a fake handler which returns NOT_IMPLEMENTED
      mapping(
        methodType,
        subpath,
        httpCodes.NOT_IMPLEMENTED,
        true
      )(Object.getPrototypeOf(resource).constructor, undefined);
    }
  }
docs: Process all methods and add @mapping decorators as necessary, so we can
  hand this off to the Routes init() function.
  
  @private
  @param {Ravel} ravelInstance - An instance of a Ravel app.
  @param {Class} resource - A reference to a Resource class.
  @param {string} methodType - The HTTP method type.
  @param {string} methodName - The name of the handler method within the class.