diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 00000000..1d181b96
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "fj"]
+	path = fj
+	url = https://codeberg.org/martianh/fj.el
diff --git a/fj b/fj
new file mode 160000
index 00000000..6dfc2c53
--- /dev/null
+++ b/fj
@@ -0,0 +1 @@
+Subproject commit 6dfc2c533c4445e282a5f9dd4825aa00c0e68ab7