added number of bids and number of flags to listing serialization

bookshare/api/serializers.py

@@ -13,22 +13,30 @@ class ListingSerializer(serializers.HyperlinkedModelSerializer):
         lookup_field = 'slug'
     )
 
-    active = serializers.SerializerMethodField('active')
-    active = serializers.SerializerMethodField('final_price')
-    active = serializers.SerializerMethodField('old')
+    active = serializers.SerializerMethodField()
+    final_price = serializers.SerializerMethodField()
+    old = serializers.SerializerMethodField()
+    num_bids = serializers.SerializerMethodField()
+    num_flags = serializers.SerializerMethodField()
 
-    def active(self, listing):
+    def get_active(self, listing):
         return listing.active()
 
-    def final_price(self, listing):
+    def get_final_price(self, listing):
         return listing.final_price()
 
-    def old(self, listing):
+    def get_old(self, listing):
         return listing.old()
 
+    def get_num_bids(self, listing):
+        return listing.bid_set.all().count()
+
+    def get_num_flags(self, listing):
+        return listing.flag_set.all().count()
+
     class Meta:
         model = Listing
         fields = ('url', 'title', 'author', 'isbn', 'year', 'edition', 'condition',
                   'access_code', 'course_abbr', 'description', 'price', 'photo',
-                  'active', 'old',
+                  'num_bids', 'num_flags', 'active', 'old',
                   'exchanged', 'cancelled', 'date_closed', 'final_price')