diff --git a/runtime.txt b/runtime.txt
new file mode 100644
index 0000000000000000000000000000000000000000..f27f1cc5ca4d2e750411e5ee682f6eb6baa674c2
--- /dev/null
+++ b/runtime.txt
@@ -0,0 +1 @@
+python-2.7.15