Add submodule snippets

snippets/clone-missing-submodules.md

@@ -0,0 +1,17 @@
+---
+title: Clone missing submodules
+tags: repository,submodule,advanced
+---
+
+Clones missing submodules and checks out commits.
+
+- Use `git submodule update --init --recursive` to clone missing submodules and checkout commits.
+
+```sh
+git submodule update --init --recursive
+```
+
+```sh
+git submodule update --init --recursive
+# Clones missing submodules and checks out commits
+```