old_contents: from django.contrib import admin
  from django.contrib.auth.models import User, Group
  from .models import Post, Comment, Upload, Author, Friending, Following
  
  # Register your models here.
  
  class AuthorInline(admin.TabularInline):
      model = Author
  
  class UserAdmin(admin.ModelAdmin):
      inlines = [
          AuthorInline,
      ]
      fields = {'username', 'password', 'is_active', 'email'}
  
  admin.site.unregister(Group)
  admin.site.unregister(User)
  admin.site.register(User, UserAdmin)
  # admin.site.register(Post)
  # admin.site.register(Comment)
  # admin.site.register(Upload)
  # admin.site.register(Author)
  # admin.site.register(Friending)
  # admin.site.register(Following)
  
  
new_contents: from django.contrib import admin
  from django.contrib.auth.models import User, Group
  from .models import Post, Comment, Upload, Author, Friending, Following
  
  # Register your models here.
  
  class AuthorInline(admin.TabularInline):
      model = Author
  
  class UserAdmin(admin.ModelAdmin):
      inlines = [
          AuthorInline,
      ]
      fields = {'username', 'is_active', 'email'}
  
  admin.site.unregister(Group)
  admin.site.unregister(User)
  admin.site.register(User, UserAdmin)
  # admin.site.register(Post)
  # admin.site.register(Comment)
  # admin.site.register(Upload)
  # admin.site.register(Author)
  # admin.site.register(Friending)
  # admin.site.register(Following)
  
  
subject: modify custom admin site