Fix serializer

CTFd/utils/exports/serializers.py

@@ -1,6 +1,6 @@
 import json
 import six
-from collections import OrderedDict
+from collections import defaultdict, OrderedDict
 
 from CTFd.utils.exports.encoders import JSONEncoder
 
@@ -9,7 +9,7 @@ class JSONSerializer(object):
     def __init__(self, query, fileobj):
         self.query = query
         self.fileobj = fileobj
-        self.buckets = []
+        self.buckets = defaultdict(list)
 
     def serialize(self):
         for row in self.query:
@@ -17,7 +17,7 @@ class JSONSerializer(object):
         self.close()
 
     def write(self, path, result):
-        self.buckets.append([result])
+        self.buckets[path].append(result)
 
     def wrap(self, result):
         result = OrderedDict([("count", len(result)), ("results", result)])
@@ -25,7 +25,7 @@ class JSONSerializer(object):
         return result
 
     def close(self):
-        for result in self.buckets:
+        for path, result in self.buckets.items():
             result = self.wrap(result)
 
             # Certain databases (MariaDB) store JSON as LONGTEXT.