打开app.json，在pages里添加first和readme页面
    添加tabBar配置，实现index和readme的切换。代码如下

    1. {
    2.   "pages": [
    3.     "pages/first/first",
    4.     "pages/readme/readme",
    5.     "pages/index/index"
    6.   ],
    7.   "window": {
    8.     "backgroundTextStyle": "light",
    9.     "navigationBarBackgroundColor": "#fff",
    10.     "navigationBarTitleText": "我的KEEP运动",
    11.     "navigationBarTextStyle": "black"
    12.   },
    13.   "tabBar": {
    14.     "color": "#a1a1a1",
    15.     "selectedColor": "rgb(108, 205, 250)",
    16.     "backgroundColor": "#ffffff",
    17.      "borderStyle":"black",
    18.     "list": [
    19.       {
    20.         "pagePath": "pages/index/index",
    21.         "iconPath": "./assets/icons/hema.png",
    22.         "selectedIconPath": "./assets/icons/hema-sel.png",
    23.         "text": "运动"
    24.       },
    25.       {
    26.         "pagePath": "pages/readme/readme",
    27.         "iconPath": "./assets/icons/mine.png",
    28.         "selectedIconPath": "./assets/icons/message.png",
    29.         "text": "了解KEEP"
    30.       }
    31.     ]
    32.   }
    33. }