[#262] Fix helper import in version 029

ckan/migration/versions/029_version_groups.py

@@ -8,7 +8,7 @@
 
 
 
-from ckan.lib.helpers import json
+import ckan.lib.helpers as h
 class JsonType(types.TypeDecorator):
     '''Store data as JSON serializing on save and unserializing on use.
     '''
@@ -19,13 +19,13 @@ def process_bind_param(self, value, engine):
             return None
         else:
             # ensure_ascii=False => allow unicode but still need to convert
-            return unicode(json.dumps(value, ensure_ascii=False))
+            return unicode(h.json.dumps(value, ensure_ascii=False))
 
     def process_result_value(self, value, engine):
         if value is None:
             return None
         else:
-            return json.loads(value)
+            return h.json.loads(value)
 
     def copy(self):
         return JsonType(self.impl.length)