old_contents: from django.contrib import admin
  from .models import Post
  # Register your models here.
  
  admin.site.register(Post)
  
new_contents: from django.contrib import admin
  from .models import Post #,FriendRequest
  # Register your models here.
  
  admin.site.register(Post)
  #admin.site.register(FriendRequest)
  
subject: add friendrequest in admin.py