diff --git a/stack.yaml.lock b/stack.yaml.lock
new file mode 100644
index 0000000..296b4d0
--- /dev/null
+++ b/stack.yaml.lock
@@ -0,0 +1,12 @@
+# This file was autogenerated by Stack.
+# You should not edit this file by hand.
+# For more information, please see the documentation at:
+#   https://docs.haskellstack.org/en/stable/lock_files
+
+packages: []
+snapshots:
+- completed:
+    size: 506303
+    url: https://raw.githubusercontent.com/commercialhaskell/stackage-snapshots/master/lts/12/18.yaml
+    sha256: 44c58c3e2bfc57455cb54ce3860847aaf69d9ee11baad238d7d0a82b7034a474
+  original: lts-12.18