fix bugs
diff --git a/plstackapi/core/api/users.py b/plstackapi/core/api/users.py
index b2ba681..7483c37 100644
--- a/plstackapi/core/api/users.py
+++ b/plstackapi/core/api/users.py
@@ -11,7 +11,7 @@
     if isinstance(filter, int):
         users = User.objects.filter(id=filter)
     elif isinstance(filter, StringTypes):
-        users = User.objects.filter(role_type=filter)
+        users = User.objects.filter(email=filter)
     elif isinstance(filter, dict):
         users = User.objects.filter(**filter)
     else: