title: How to Serialize BigIntegerField, TextField in serializer Django
body: <p>I have a model which has following attributes</p>
  
  <pre><code>from django.db import models
  class ApiLogs(models.Model):
      user_id = models.BigIntegerField(null=True)
      ip = models.CharField(max_length=16)
      user_agent = models.TextField(blank=True, null=True)
      client = models.CharField(max_length=50, blank=True, null=True)
      client_version = models.CharField(max_length=50, blank=True, null=True)
      token = models.TextField(blank=True, null=True)
      uri = models.CharField(max_length=200)
      method = models.CharField(max_length=20)
  </code></pre>
  
  <p>I have defined a serializer  </p>
  
  <pre><code>from rest_framework import serializers
  class ApiSerializer(serializers.Serializer):
      user_id = serializers.BigIntegerField( allow_null=True)
      ip = serializers.CharField(max_length=16)
      user_agent = serializers.TextField(allow_blank=True, allow_null=True)
      client = serializers.CharField(max_length=50, allow_blank=True, allow_null=True)
      client_version = serializers.CharField(max_length=50, allow_blank=True, allow_null=True)
      token = serializers.TextField(allow_blank=True, allow_null=True)
      uri = serializers.CharField(max_length=200)
      method = serializers.CharField(max_length=20)
  </code></pre>
  
  <p>But it is showing error somewhat like this</p>
  
  <pre><code>user_id = serializers.BigIntegerField( allow_null=True)
  AttributeError: 'module' object has no attribute 'BigIntegerField'
  </code></pre>
  
  <p>for textfield</p>
  
  <pre><code>user_agent = serializers.TextField(allow_blank=True, allow_null=True)
  AttributeError: 'module' object has no attribute 'TextField'
  </code></pre>
  
  <p>Now how to serialize this type of data.</p>