Added as much tests as possible

backend/.gitignore

@@ -0,0 +1,5 @@
+node_modules/
+*.db
+*.db-shm
+*.db-wal
+vapid_keys.json

backend/db.js

@@ -0,0 +1,26 @@
+'use strict';
+
+const { DatabaseSync } = require('node:sqlite');
+const path = require('path');
+
+const DB_PATH = process.env.DB_PATH || path.join(__dirname, 'swipes.db');
+
+const db = new DatabaseSync(DB_PATH);
+
+db.exec(`
+  CREATE TABLE IF NOT EXISTS swipes (
+    id          INTEGER PRIMARY KEY AUTOINCREMENT,
+    profile_id  TEXT    NOT NULL,
+    profile_name TEXT   NOT NULL,
+    action      TEXT    NOT NULL CHECK(action IN ('like', 'nope', 'superlike')),
+    swiped_at   TEXT    NOT NULL
+  );
+
+  CREATE TABLE IF NOT EXISTS push_subscriptions (
+    user_id      TEXT PRIMARY KEY,
+    subscription TEXT NOT NULL,
+    created_at   TEXT NOT NULL
+  );
+`);
+
+module.exports = db;