Add initial DB schema and connection pool

src/db/migrations.sql

@@ -0,0 +1,22 @@
+-- Migration 001: initial schema
+CREATE EXTENSION IF NOT EXISTS "pgcrypto";
+
+CREATE TABLE users (
+    id          UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    username    VARCHAR(64)  UNIQUE NOT NULL,
+    email       VARCHAR(255) UNIQUE NOT NULL,
+    password_hash TEXT NOT NULL,
+    created_at  TIMESTAMPTZ  DEFAULT NOW(),
+    updated_at  TIMESTAMPTZ  DEFAULT NOW()
+);
+
+CREATE TABLE sessions (
+    id          UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    user_id     UUID NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    token_hash  TEXT NOT NULL,
+    created_at  TIMESTAMPTZ DEFAULT NOW(),
+    expires_at  TIMESTAMPTZ NOT NULL
+);
+
+CREATE INDEX idx_sessions_user_id ON sessions(user_id);
+CREATE INDEX idx_sessions_expires_at ON sessions(expires_at);

src/db/pool.rs

@@ -0,0 +1,7 @@
+use sqlx::PgPool;
+use std::env;
+
+pub async fn create_pool() -> Result<PgPool, sqlx::Error> {
+    let url = env::var("DATABASE_URL").expect("DATABASE_URL must be set");
+    PgPool::connect(&url).await
+}