diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..ab52abc
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "challenges/h4tum2025/mosaic"]
+	path = challenges/h4tum2025/mosaic
+	url = ssh://git@gitea.cato447.de:222/cato447/mosaic.git
diff --git a/challenges/README.md b/challenges/README.md
new file mode 100644
index 0000000..634a5c4
--- /dev/null
+++ b/challenges/README.md
@@ -0,0 +1,9 @@
+# Purpose
+
+This subfolder contains ideas for ctf challenges.
+
+#### Adding challenges
+
+Every challenge is developed in its own repository. I try to collect them here via git submodules.
+
+