WARNINGS:
?: (urls.W001) Your URL pattern '^$' uses include with a route ending with a '$'. Remove the dollar from the route to avoid problems including URLs.
从Django2.0开始：
1.把url函数换成path
2.不在使用^、$作为路由
from django.contrib import admin
from django.urls import path #此处应用path，老板本使用的是url
from appchat import views
urlpatterns = [
path('admin/', admin.site.urls),
path('login/', views.acc_login,name='login'),
path('logout/', views.acc_logout, name='logout'),
path('',views.index,name='index'), #此处设置为首页，以前写法是'^$',新版本不再使用^、$，只需要‘’就可以
]