diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..3d7df14
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "docs/_themes"]
+	path = docs/_themes
+	url = https://github.com/mitsuhiko/flask-sphinx-themes.git
diff --git a/docs/_themes b/docs/_themes
new file mode 160000
index 0000000..0269f3d
--- /dev/null
+++ b/docs/_themes
@@ -0,0 +1 @@
+Subproject commit 0269f3d188eaff07c44a800f35f7351f9e0aefb0