docs: Create LESSONS.md file

LESSONS.md

@@ -0,0 +1,113 @@
+# Lessons
+
+## Table of Contents
+
+1. [📦 Git LFS (Large File Storage)](#1-git-lfs-large-file-storage)
+2. [🌊 Marimo: Code Display Behavior](#2-marimo-code-display-behavior)
+
+## 1. 📦 Git LFS (Large File Storage)
+
+Git LFS (Large File Storage) is an extension for Git that allows you to track and version large files (e.g. `.db`, `.csv`, `.model`) without bloating your repository. Instead of storing the actual file content in Git, it stores a lightweight pointer and pushes the real content to a separate LFS server.
+
+---
+
+### How to Install
+
+```bash
+sudo apt install git-lfs
+```
+
+After installation, initialize LFS:
+
+```bash
+git lfs install
+```
+
+---
+
+### How to Use (Basic Example)
+
+1. **Track the file type or name:**
+
+   ```bash
+   git lfs track "olist.db"
+   ```
+
+2. **Edit `.gitignore` **
+
+   ```bash
+   # Ignore all database files
+   *.db
+   # But include this one (make sure it's tracked with git LFS)
+   !olist.db
+   ```
+
+3. **Stage the tracking file (`.gitattributes`) and your large file:**
+
+   ```bash
+   git add .gitattributes
+   git add olist.db
+   git commit -m "Track olist.db with Git LFS"
+   ```
+
+4. **Push to your remote repo:**
+
+   ```bash
+   git push origin main
+   ```
+
+## 2. 🌊 Marimo: Code Display Behavior
+
+By default, **Marimo hides the code cells** in the deployed (read-only) version of your app, especially when running as a Hugging Face Space or a `.py` script.
+
+This behavior is intentional and aligns with Marimo’s goal of turning Python notebooks into polished, interactive **data apps** — focusing on the results and UI rather than code.
+
+| Environment                          | Notes                              |
+| ------------------------------------ | ---------------------------------- |
+| Local Dev Mode (`marimo run app.py`) | Full interactivity + visible code  |
+| Deployed App (e.g., HF Spaces)       | Only outputs / UI components shown |
+
+**If you want to show the code:**
+
+You can **explicitly render code** using `mo.ui.code()` or `mo.md()` with fenced code blocks:
+
+```python
+code = '''
+revenue_by_month_year = query_results[QueryEnum.REVENUE_BY_MONTH_YEAR.value]
+revenue_by_month_year
+'''
+
+mo.ui.code(code, language="python")
+```
+
+Or in Markdown:
+
+````python
+mo.md("""```python
+revenue_by_month_year = ...
+revenue_by_month_year
+```""")
+````
+
+Or set a global config int hte app header
+
+```py
+__marimo__ = {
+    "hide_code": False  # or True to hide all
+}
+```
+
+### 💡 Tip:
+
+If your app is intended as a tutorial or learning resource, you can:
+
+- Create a separate `notebook.md` or `.ipynb` with all code visible
+- Link to that from the main app using `mo.md("[View full notebook](./notebook.md)")`
+- Use Marimo's UI components to conditionally show/hide code with toggles
+
+  ```python
+  show_code = mo.ui.checkbox(value=False, label="Show Code")
+
+  if show_code.value:
+      mo.ui.code(code)
+  ```