code: function CommandsAdapter() {
      var tplFile = fs.readFileSync(path.join(__dirname, '../templates/commands.tpl')).toString();
      var compiled = _.template(tplFile);
      this.createTemplate = function (provisionerConfig) {
          return compiled({
              config: provisionerConfig,
              commands: provisionerConfig.config.commands
          });
      };
  }
docs: Each provisioner implements .createTemplate(provisionerConfig) which returns string which is text that will be
  injected into each provisioner's config in Vagrantfile