Added Document.reload method

mongoengine/document.py

@@ -64,6 +64,14 @@ class Document(BaseDocument):
         object_id = self._fields['id'].to_mongo(self.id)
         self.__class__.objects(id=object_id).delete()
 
+    def reload(self):
+        """Reloads all attributes from the database.
+        """
+        object_id = self._fields['id'].to_mongo(self.id)
+        obj = self.__class__.objects(id=object_id).first()
+        for field in self._fields:
+            setattr(self, field, getattr(obj, field))
+
     def validate(self):
         """Ensure that all fields' values are valid and that required fields
         are present.