diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..de1c242
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "themes/maddybook"]
+	path = themes/maddybook
+	url = https://github.com/makyo/maddybook.git