diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000000000000000000000000000000000000..79834637f1896b90c6285ebd384d572d0486f738
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "_code/extern/optimization"]
+	path = _code/extern/optimization
+	url = ssh://git@gitlab.cba.mit.edu:846/erik/optimization.git
diff --git a/_code/extern/optimization b/_code/extern/optimization
new file mode 160000
index 0000000000000000000000000000000000000000..c87a5e0e10d42eab8a7a74191af8127301a0dbac
--- /dev/null
+++ b/_code/extern/optimization
@@ -0,0 +1 @@
+Subproject commit c87a5e0e10d42eab8a7a74191af8127301a0dbac