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

    this.commands = {
      install: {
        usage: 'Install a Serverless service from GitHub or a plugin from the Serverless registry',
        lifecycleEvents: ['install'],
        options: {
          url: {
            usage: 'URL of the Serverless service on GitHub',
            required: true,
            shortcut: 'u',
          },
          name: {
            usage: 'Name for the service',
            shortcut: 'n',
          },
        },
      },
    };

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