old_contents: from handover_api.models import Handover, Draft, User
  from rest_framework import serializers
  
  
  class HandoverSerializer(serializers.HyperlinkedModelSerializer):
      class Meta:
          model = Handover
          fields = ('project_id','from_user_id','to_user_id','state')
  
  
  class DraftSerializer(serializers.HyperlinkedModelSerializer):
      class Meta:
          model = Draft
          fields = ('project_id','from_user_id','to_user_id','state')
  
  
  class UserSerializer(serializers.HyperlinkedModelSerializer):
      class Meta:
          model = User
          fields = ('dds_id', 'api_key')
new_contents: from handover_api.models import Handover, Draft, User
  from rest_framework import serializers
  
  
  class HandoverSerializer(serializers.HyperlinkedModelSerializer):
      class Meta:
          model = Handover
          fields = ('id','url','project_id','from_user_id','to_user_id','state')
  
  
  class DraftSerializer(serializers.HyperlinkedModelSerializer):
      class Meta:
          model = Draft
          fields = ('id','url','project_id','from_user_id','to_user_id','state')
  
  
  class UserSerializer(serializers.HyperlinkedModelSerializer):
      class Meta:
          model = User
          fields = ('id','url','dds_id', 'api_key')
subject: Include id and url in models