title: Using Django-taggit and django-taggit-serializer with issue
body: <p>I am trying to add tags in my model by taggit and taggit serializer. I making my API in rest framework. 
  I followed the instruction（<a href="https://github.com/glemmaPaul/django-taggit-serializer" rel="nofollow noreferrer">https://github.com/glemmaPaul/django-taggit-serializer</a>） but it is still an issues:</p>
  
  <blockquote>
    <p>"tags": [
            "Invalid json list. A tag list submitted in string form must be valid json."]</p>
  </blockquote>
  
  <p>/setting.py</p>
  
  <pre><code>INSTALLED_APPS = [
    [...]
  'rest_framework',
  'taggit',
  'taggit_serializer',
  ]
  </code></pre>
  
  <p>/models.py</p>
  
  <pre><code>tags = TaggableManager(blank = True) 
  </code></pre>
  
  <p>/serializer.py</p>
  
  <pre><code>class JobSerializer(TaggitSerializer,serializers.HyperlinkedModelSerializer):
  
  # tag serializer
  tags = TagListSerializerField()
  </code></pre>
  
  <p>There is noting changed in the view.py.</p>
  
  <p>thanks @ykh for helping me to solve this problem, but it comes to new situation with error:</p>
  
  <p>when you want to initial the value:</p>
  
  <pre><code>hao,free
  </code></pre>
  
  <p>the outcome will be like that:   </p>
  
  <pre><code> "tags": [
      "hao",
      "free"
  ],
  </code></pre>
  
  <p><strong>But</strong> when I intend to put updates into this value:
  it showed the Json file in rest framework automatically:</p>
  
  <p><a href="https://i.stack.imgur.com/3ZcKP.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/3ZcKP.png" alt="enter image description here"></a></p>
  
  <p>and if you put data to your api, the result will be:</p>
  
  <p><a href="https://i.stack.imgur.com/8emJ4.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/8emJ4.png" alt="enter image description here"></a></p>
  
  <p><strong>The issue is that each time when I try to modify the instance which including the 'tag' in rest framework, brackets and line breaks were automatic attached added in 'tag' field, like the picture result shows</strong></p>
  
  <hr>
  
  <p>Update:
  It seems that I have solved this issue, the solution is overriding the create function in serializer:</p>
  
  <blockquote>
    <p>using django-taggit-serializer. and</p>
  </blockquote>
  
  <pre><code>    def create(self, validated_data):
      tags = validated_data.pop('tags')
      instance = super(JobSerializer, self).create(validated_data)
      instance.tags.set(*tags)
      return instance
  </code></pre>