diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..0b67f8b
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "external/bioptim"]
+	path = external/bioptim
+	url = https://github.com/Kev1CO/bioptim