ADDED   .github/mergeable.yml
Index: .github/mergeable.yml
==================================================================
--- .github/mergeable.yml
+++ .github/mergeable.yml
@@ -0,0 +1,11 @@
+version: 2
+mergeable:
+  - when: pull_request.opened
+    name: "Greet a contributor"
+    validate: []
+    pass:
+      - do: comment
+        payload:
+          body: >
+            Thanks for your contribution!  Unfortunately, we don't use GitHub pull requests to manage code contributions to this repository.  Instead, please see the [REDUCE Homepage](https://reduce-algebra.sourceforge.io/) for details on how to get involved with REDUCE.
+      - do: close