code: function plugin(Vue) {
  
      if (plugin.installed) {
          return;
      }
  
      Util(Vue);
  
      Vue.url = Url;
      Vue.http = Http;
      Vue.resource = Resource;
      Vue.Promise = PromiseObj;
  
      Object.defineProperties(Vue.prototype, {
  
          $url: {
              get: function get() {
                  return options(Vue.url, this, this.$options.url);
              }
          },
  
          $http: {
              get: function get() {
                  return options(Vue.http, this, this.$options.http);
              }
          },
  
          $resource: {
              get: function get() {
                  return Vue.resource.bind(this);
              }
          },
  
          $promise: {
              get: function get() {
                  var this$1 = this;
  
                  return function (executor) { return new Vue.Promise(executor, this$1); };
              }
          }
  
      });
  }
docs: Install plugin.