upgrade postgres

README.md

@@ -6,7 +6,7 @@ A self-hosted RSS reader: a Rust/actix-web + Diesel/PostgreSQL backend with a Vu
 
 - **Backend**: Rust, actix-web, Diesel ORM, PostgreSQL, JWT auth
 - **Frontend**: Vue 3, Vite, axios
-- **Database**: PostgreSQL 15
+- **Database**: PostgreSQL 18
 
 ---
 
@@ -126,7 +126,7 @@ docker compose up --build -d
 
 This builds three images and starts them on a shared network:
 
-- **`postgres`** — PostgreSQL 15, data persisted in the `postgres_data` volume, reachable on `localhost:5432`
+- **`postgres`** — PostgreSQL 18, data persisted in the `postgres_data` volume, reachable on `localhost:5432`
 - **`backend`** — multi-stage build (compiles the Rust binary in a `rust:slim` builder, runs it in a slim `debian` runtime image); runs embedded Diesel migrations automatically on startup; listens on `0.0.0.0:8001`
 - **`frontend`** — multi-stage build (compiles the Vue app with `node:20-alpine`, serves the static bundle with `nginx:alpine`); listens on `0.0.0.0:8080` and proxies `/api/` to the `backend` service over Docker's internal network