old_contents: from django.contrib import admin
  
  from .models import Post, Category
  from dpb.admin import PageDownAdmin
  
  
  @admin.register(Post)
  class PostAdmin(PageDownAdmin):
      list_display = ('title', 'category', 'archive', 'public', 'created')
      list_filter = ['created']
      search_fields = ['title']
      fieldsets = [
          (None,        {'fields': ['title', 'category', 'file', ('archive', 'public'), 'content']}),
          ('Erweitert', {'fields': ['created', 'author'], 'classes': ['collapse']}),
      ]
  
      def save_model(self, request, obj, form, change):
          # Automatic set author if None is set
          if getattr(obj, 'author', None) is None:
              obj.author = request.user
          obj.save()
  
  
  admin.site.register(Category)
  
new_contents: from django.contrib import admin
  
  from dpb.admin import PageDownAdmin
  from .models import Post, Category
  
  
  @admin.register(Post)
  class PostAdmin(PageDownAdmin):
      list_display = ('title', 'category', 'archive', 'public', 'created')
      list_filter = ['created']
      search_fields = ['title']
      readonly_fields = ['created']
      fieldsets = [
          (None, {'fields': ['title', 'category', 'file', ('archive', 'public'), 'content']}),
          ('Erweitert', {'fields': ['created', 'author'], 'classes': ['collapse']}),
      ]
  
      def save_model(self, request, obj, form, change):
          # Automatic set author if None is set
          if getattr(obj, 'author', None) is None:
              obj.author = request.user
          obj.save()
  
  
  admin.site.register(Category)
  
subject: Make created a read-only field in admin