Add tags in article API responses

apps/rp/api/serializers.py

 from rest_framework import serializers
 
+from taggit.managers import TaggableManager
 from rp.models import Article
 
+class TagListSerializer(serializers.Field):
+    class Meta:
+        model = TaggableManager(blank=True)
+
+    def to_representation(self, obj):
+        if type(obj) is not list:
+            return [tag.name for tag in obj.all()]
+        return obj
 
 class ArticleSerializer(serializers.ModelSerializer):
+    tags = TagListSerializer()
+
     class Meta:
         model = Article
-        fields = ('id', 'url', 'title', 'extracts', 'und_score_up', 'und_score_down')
+        fields = ('id', 'url', 'title', 'tags', 'extracts', 'und_score_up', 'und_score_down')