first commit of refactor

backend/infra/database.js

@@ -0,0 +1,32 @@
+import pg from "pg";
+import dotenv from "dotenv";
+
+dotenv.config();
+
+const { Pool } = pg;
+
+const pool = new Pool(
+  process.env.DATABASE_URL
+    ? { connectionString: process.env.DATABASE_URL }
+    : {
+        host: process.env.DB_HOST || "localhost",
+        port: process.env.DB_PORT || 5432,
+        user: process.env.DB_USER,
+        password: process.env.DB_PASSWORD,
+        database: process.env.DB_NAME,
+        max: 20,
+        idleTimeoutMillis: 30000,
+        connectionTimeoutMillis: 2000,
+      }
+);
+
+pool.on("connect", () => {
+  console.log("Connected to PostgreSQL database");
+});
+
+pool.on("error", (err) => {
+  console.error("Unexpected error on idle client", err);
+  process.exit(1);
+});
+
+export default pool;