title: How to create nested serialization from mutliple models uisng django rest framewrok
body: <p>I am trying to create nested relationship from more than two models in Django Rest Framework.
  Thank you in advance for helping me.
  I succeed with two models but when I'm trying with three models unable to create nested serialization.</p>
  <pre><code>
  from django.db import models
  
  class Project(models.Model):
    project_id = models.AutoField(primary_key=True)
    project_name = models.CharField(max_length=255)
    
    def __str__(self):
      return self.name
  
  class Site(models.Model):
    site_id =  models.AutoField(primary_key=True)
    site_name = models.CharField(max_length=255)
    project_id= models.ForeignKey(Project, related_name=&quot;projectid&quot;, on_delete=models.CASCADE)
    
    def __str__(self):
      return self.site_name 
  class Aggin(models.Model):
     assign_id = models.AutoField(primary_key=True)
     site_id = Models.ForeginKey(Site, relate_name=&quot;siteid&quot;, on_delete=models.CASCADE)
    
  </code></pre>
  <pre><code>from rest_framework import serializers
  from .models import Song, Artist
  
  
  class ProjectSerializer(serializers.ModelSerializer):
      class Meta:
        model = Project
        fields = ('__all__')
        
  class SiteSerializer(serializers.ModelSerializer):
    
     
    class Meta:
      model = Site
      fields = ('__all__')
  
  class AggignSerializer(serializers.ModelSerializer)
    class Meta:
       model = Aggin
       fields = ('__all__')
  </code></pre>