diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..f3b3632
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "writedown"]
+	path = writedown
+	url = https://github.com/dyne/writedown
diff --git a/writedown b/writedown
new file mode 160000
index 0000000..e56a5c1
--- /dev/null
+++ b/writedown
@@ -0,0 +1 @@
+Subproject commit e56a5c17417a4e6101d9abfeeab055af72a2571c