umi配置redux，不是dva

    背景：umi3

    首先要建个umi项目，建好后 npm i react-redux。再根据千辛万苦翻到的文档，建个src/app.js文件：

import React from "react";
import { Provider } from "react-redux";

const rootReducer = (state = {}, action) => state;
const store = createStore(rootReducer);

export function rootContainer(root) {
  return <Provider store={store}>{root}</Provider>;
}

    好了。元旦节快乐。