Add Later app as submodule in showcase

Author: brandonkachen

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "showcase/later"]
+	path = showcase/later
+	url = https://github.com/narthur/later

showcase/README.md

@@ -1,2 +1,20 @@
 # showcase
 Community showcase of projects built by Codebuff
+
+## Projects
+
+- [Later](https://github.com/narthur/later) - A task management app inspired by Do It (Tomorrow), built with Svelte
+
+## Cloning
+
+This repository contains submodules. To clone including all showcase projects, use:
+
+```bash
+git clone --recursive https://github.com/CodebuffAI/codebuff-community.git
+```
+
+Or if you've already cloned the repository:
+
+```bash
+git submodule update --init --recursive
+```