Add ability to set Schema fields through the serializer Meta class (#134)

* Add swagger_schema_fields attribute to serializer Meta class
* Add documentation

Closes #132.

testproj/todo/serializer.py

@@ -1,3 +1,5 @@
+from collections import OrderedDict
+
 from django.utils import timezone
 from rest_framework import serializers
 from rest_framework_recursive.fields import RecursiveField
@@ -26,6 +28,15 @@ class TodoYetAnotherSerializer(serializers.ModelSerializer):
         model = TodoYetAnother
         fields = ('title', 'todo')
         depth = 2
+        swagger_schema_fields = {
+            'example': OrderedDict([
+                ('title', 'parent'),
+                ('todo', OrderedDict([
+                    ('title', 'child'),
+                    ('todo', None),
+                ])),
+            ])
+        }
 
 
 class TodoTreeSerializer(serializers.ModelSerializer):