diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..32abb67
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "preprocessing-ng"]
+	path = preprocessing-ng
+	url = https://github.com/KatherLab/preprocessing-ng
diff --git a/preprocessing-ng b/preprocessing-ng
new file mode 160000
index 0000000..2776b69
--- /dev/null
+++ b/preprocessing-ng
@@ -0,0 +1 @@
+Subproject commit 2776b6957003ad3fa50aa0625f3ca37c7069521a