Use Tidelift's process for security issues

README.md

@@ -891,6 +891,12 @@ both in the same application. If both are present, Ransack will default to
 Active Record only. The logic is contained in
 `Ransack::Adapters#instantiate_object_mapper` should you need to override it.
 
+## Security contact information
+
+Please use the Tidelift security contact to [report a security
+vulnerability](https://tidelift.com/security).  Tidelift will coordinate the fix
+and disclosure.
+
 ## Semantic Versioning
 
 Ransack attempts to follow semantic versioning in the format of `x.y.z`, where: