diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..bc67117
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "2015"]
+	path = 2015
+	url = ../aoc2015.git
diff --git a/2015 b/2015
new file mode 160000
index 0000000..0000044
--- /dev/null
+++ b/2015
@@ -0,0 +1 @@
+Subproject commit 00000440419b77af439437c2be90a875fd315d9b