expand groups on contacts list for a campaign

picampaign/campaign/serializers.py

 from picampaign.campaign.models import (Campaign, CampaignContact,
                                         Argumentary)
+from picampaign.organization.serializers import GroupSerializer
 from rest_framework import serializers
 
 
@@ -22,7 +23,7 @@ class CampaignContactSerializer(serializers.HyperlinkedModelSerializer):
     first_name = serializers.Field(source='contact.first_name')
     last_name = serializers.Field(source='contact.last_name')
     phone = serializers.Field(source='contact.phone')
-    groups = serializers.Field(source='all_groups')
+    groups = GroupSerializer(many=True, source='contact.groups')
     contact_id = serializers.Field(source='contact.id')
 
     class Meta:

picampaign/organization/serializers.py

-from picampaign.organization.models import FeedbackCategory
+from picampaign.organization.models import FeedbackCategory, Group
 from rest_framework import serializers
 
 
@@ -7,3 +7,11 @@ class CategorySerializer(serializers.ModelSerializer):
     class Meta:
         model = FeedbackCategory
         fields = ('id', 'name')
+
+
+class GroupSerializer(serializers.ModelSerializer):
+    type = serializers.Field(source='type.name')
+
+    class Meta:
+        model = Group
+        fields = ('type', 'name', 'media')