lib/plugins/login/login.js/Login/constructor
class Login:  constructor(serverless, options) {
    this.serverless = serverless;
    this.options = options;

    this.commands = {
      login: {
        usage: 'Login or sign up for the Serverless Platform',
        lifecycleEvents: ['login'],
        platform: true,
      },
    };

    this.hooks = {
      'login:login': () => BbPromise.bind(this).then(this.login),
    };
  }