feat: Add deploy-fullstack-vercel skill

assistant/src/config/vellum-skills/deploy-fullstack-vercel/SKILL.md

@@ -0,0 +1,179 @@
+---
+name: "Deploy Fullstack to Vercel"
+description: "Build and deploy a full-stack app (React frontend + Python/FastAPI backend) to Vercel as a serverless demo with seeded data"
+metadata: {"vellum": {"emoji": "🚀"}}
+
+---
+
+# Deploy Fullstack to Vercel
+
+Deploy a full-stack app with a React/Vite frontend and Python/FastAPI backend to Vercel as a serverless demo. No auth required — meant for demos, portfolio pieces, and quick showcases.
+
+## When to Use
+
+- User says "deploy this to Vercel", "host this", "publish this"
+- User has a project with a frontend + backend they want live
+- User wants a quick demo deployment (no persistent database needed)
+
+## Prerequisites
+
+- A project with a frontend (React/Vite) and backend (FastAPI/Python)
+- Vercel CLI installed (`npm install -g vercel`) and authenticated (`vercel login`)
+
+## Workflow
+
+### 1. Build the Frontend
+
+```bash
+cd <project>/frontend
+npm install
+npx vite build
+```
+
+This produces static files in `frontend/dist/`.
+
+### 2. Create the Vercel Deploy Directory
+
+```
+<project>/vercel-deploy/
+├── api/
+│   ├── index.py          ← FastAPI app wrapper (entry point)
+│   ├── database.py        ← DB config (use /tmp for SQLite)
+│   ├── models.py
+│   ├── schemas.py
+│   ├── seed_data.py       ← Must seed ALL required data (users, etc.)
+│   ├── routers/
+│   │   ├── __init__.py
+│   │   └── *.py
+│   └── requirements.txt   ← Python deps (fastapi, sqlalchemy, pydantic)
+├── index.html             ← From frontend/dist/
+├── assets/                ← From frontend/dist/assets/
+└── vercel.json
+```
+
+**Key steps:**
+```bash
+mkdir -p <project>/vercel-deploy/api
+
+# Copy frontend build output to deploy root
+cp -r <project>/frontend/dist/* <project>/vercel-deploy/
+
+# Copy backend files into api/
+cp <project>/backend/models.py <project>/vercel-deploy/api/
+cp <project>/backend/database.py <project>/vercel-deploy/api/
+cp <project>/backend/schemas.py <project>/vercel-deploy/api/
+cp <project>/backend/seed_data.py <project>/vercel-deploy/api/
+cp -r <project>/backend/routers <project>/vercel-deploy/api/
+cp <project>/backend/requirements.txt <project>/vercel-deploy/api/
+```
+
+### 3. Create api/index.py (Serverless Entry Point)
+
+```python
+import sys, os
+sys.path.insert(0, os.path.dirname(__file__))
+
+from fastapi import FastAPI
+from fastapi.middleware.cors import CORSMiddleware
+from database import engine, Base, SessionLocal
+from seed_data import seed_exercises, seed_default_user  # all seed functions
+from routers import users, exercises, workouts, schedule, progress
+
+# Create tables and seed on EVERY cold start
+Base.metadata.create_all(bind=engine)
+db = SessionLocal()
+try:
+    seed_exercises(db)
+    seed_default_user(db)  # IMPORTANT: seed all required data
+finally:
+    db.close()
+
+app = FastAPI(title="MyApp")
+
+app.add_middleware(
+    CORSMiddleware,
+    allow_origins=["*"],
+    allow_credentials=True,
+    allow_methods=["*"],
+    allow_headers=["*"],
+)
+
+app.include_router(users.router)
+# ... other routers
+
+@app.get("/api/health")
+def health_check():
+    return {"status": "ok"}
+```
+
+### 4. Update database.py for Vercel
+
+**Critical:** Vercel serverless functions can only write to `/tmp`. Update the SQLite path:
+
+```python
+SQLALCHEMY_DATABASE_URL = "sqlite:////tmp/app.db"
+```
+
+### 5. Seed ALL Required Data
+
+**This is the #1 gotcha.** Since `/tmp` is ephemeral, every cold start gets a fresh database. If your frontend assumes certain data exists (like user ID 1), you MUST seed it:
+
+```python
+def seed_default_user(db: Session):
+    count = db.query(UserProfile).count()
+    if count > 0:
+        return
+    user = UserProfile(name="Demo User", ...)
+    db.add(user)
+    db.commit()
+```
+
+### 6. Create vercel.json
+
+```json
+{
+  "rewrites": [
+    { "source": "/api/(.*)", "destination": "/api/index.py" },
+    { "source": "/((?!assets/).*)", "destination": "/index.html" }
+  ]
+}
+```
+
+This routes:
+- `/api/*` → Python serverless function
+- Everything else → React SPA (index.html)
+
+### 7. Deploy
+
+```bash
+cd <project>/vercel-deploy
+vercel --yes --prod
+```
+
+### 8. Verify
+
+```bash
+curl -s <deployed-url>/api/health
+# Should return: {"status":"ok"}
+```
+
+## Gotchas & Limitations
+
+| Issue | Solution |
+|-------|----------|
+| SQLite resets on cold start | Seed ALL required data in index.py startup |
+| No persistent storage | Acceptable for demos. For production, use Vercel Postgres or Supabase |
+| No auth | Fine for demos/portfolios. Add auth layer for real apps |
+| `requirements.txt` location | Must be inside `api/` folder (next to index.py) |
+| Module imports in routers | Use `sys.path.insert(0, os.path.dirname(__file__))` in index.py |
+| CORS | Set `allow_origins=["*"]` for demo deployments |
+| `--name` flag deprecated | Don't use `--name` with Vercel CLI, just deploy from the directory |
+
+## Vercel CLI Quick Reference
+
+```bash
+npm install -g vercel    # Install
+vercel login             # Authenticate (opens browser)
+vercel --yes --prod      # Deploy to production (skip prompts)
+vercel logs --project <name>  # Check function logs
+```