chore: use shared postgres for family wishlist

README.md

@@ -5,7 +5,7 @@ A small, private wishlist app for two users. Each user has their own profile, sl
 - **Backend**: Node.js 20, Fastify 4, Prisma 5, PostgreSQL 16
 - **Frontend**: React 18, Vite 5, Tailwind CSS, TanStack Query, React Hook Form + Zod
 - **Monorepo**: pnpm workspaces
-- **Deploy**: Docker Compose (Postgres + backend + nginx-served frontend)
+- **Deploy**: Docker Compose (shared Postgres + backend + nginx-served frontend)
 
 ---
 
@@ -32,7 +32,7 @@ apps/
 packages/
   shared/     zod schemas + DTO types shared between backend and frontend
 docker/       Dockerfiles + nginx.conf
-docker-compose.yml        prod stack (postgres + backend + frontend)
+docker-compose.yml        prod stack (shared postgres + backend + frontend)
 docker-compose.dev.yml    dev helper (postgres only)
 .env.example  full env template
 ```
@@ -127,10 +127,11 @@ Review the rest of `.env`:
 
 - `USER1_USERNAME`, `USER1_SLUG`, `USER1_DISPLAY_NAME`
 - `USER2_USERNAME`, `USER2_SLUG`, `USER2_DISPLAY_NAME`
-- `POSTGRES_*` (used by Docker)
+- `DB_HOST=postgres_budget`, `DB_PORT=5432`, `DB_NAME=db_family`
+- `DB_USER`, `DB_PASSWORD`, `DATABASE_URL` (sensitive values stay only in `.env`)
 - `PUBLIC_APP_URL` (used for CORS in production)
 
-### 3. Run everything via Docker
+### 3. Run the shared Docker stack
 
 ```bash
 docker compose up --build
@@ -139,12 +140,18 @@ docker compose up --build
 Opens:
 
 - Frontend: http://localhost:8080
-- Backend API: http://localhost:8080/api (proxied by nginx) or http://localhost:3000 if you map `backend`
-- Postgres: internal only
+- Backend API: http://localhost:8080/api (proxied by nginx) or http://localhost:3000 if you map `family-wishlist-backend`
+
+Before first start, create a dedicated database and user for this project in the existing Postgres host:
+
+- host: `postgres_budget`
+- port: `5432`
+- database: `db_family`
+- user/password: set only in `.env` and do not commit them
 
 On first start, the backend:
 
-1. Runs `prisma db push` against the Postgres service (creates tables from `schema.prisma`; idempotent).
+1. Runs `prisma db push` against the configured shared Postgres database (creates tables from `schema.prisma`; idempotent).
 2. Seeds/upserts both users from env (public fields only — password hash stays in env).
 3. Starts Fastify on port 3000.
 4. Registers the daily trash-purge cron (runs at 03:17 UTC, also once on startup).
@@ -159,7 +166,7 @@ Run Postgres in a container, apps on the host:
 ```bash
 docker compose -f docker-compose.dev.yml up -d
 # Override DATABASE_URL to point to localhost:
-# DATABASE_URL=postgresql://wishlist:change_me@localhost:5432/family_wishlist
+# DATABASE_URL=postgresql://<DB_USER>:<DB_PASSWORD>@localhost:5432/db_family
 
 pnpm --filter @family-wishlist/backend prisma:push    # apply schema (first time and on schema changes)
 pnpm --filter @family-wishlist/backend seed           # upsert two users from env into DB
@@ -170,6 +177,9 @@ This starts both apps in parallel:
 
 - Frontend: http://localhost:5173 (proxying `/api` and `/uploads` to http://localhost:3000)
 - Backend: http://localhost:3000
+- Dev Postgres: `localhost:5432` for local-only development data
+
+The dev compose file stays isolated from the shared `postgres_budget` instance. Keep production credentials and local credentials in `.env`, and never hardcode them in compose files or source code.
 
 ### 5. Useful scripts