feat(backend): PostgreSQL connection with Drizzle ORM + base schema

apps/backend/drizzle.config.ts

@@ -0,0 +1,10 @@
+import { defineConfig } from 'drizzle-kit';
+
+export default defineConfig({
+  schema: './src/db/schema.ts',
+  out: './drizzle',
+  dialect: 'postgresql',
+  dbCredentials: {
+    url: process.env['DATABASE_URL'] ?? '',
+  },
+});

apps/backend/drizzle/0000_init.sql

@@ -0,0 +1,19 @@
+CREATE TABLE "users" (
+	"id" uuid PRIMARY KEY DEFAULT gen_random_uuid() NOT NULL,
+	"username" text,
+	"avatar_url" text,
+	"created_at" timestamp DEFAULT now() NOT NULL,
+	"updated_at" timestamp DEFAULT now() NOT NULL,
+	CONSTRAINT "users_username_unique" UNIQUE("username")
+);
+--> statement-breakpoint
+CREATE TABLE "wallets" (
+	"id" uuid PRIMARY KEY DEFAULT gen_random_uuid() NOT NULL,
+	"user_id" uuid NOT NULL,
+	"address" text NOT NULL,
+	"is_primary" boolean DEFAULT false NOT NULL,
+	"created_at" timestamp DEFAULT now() NOT NULL,
+	CONSTRAINT "wallets_address_unique" UNIQUE("address")
+);
+--> statement-breakpoint
+ALTER TABLE "wallets" ADD CONSTRAINT "wallets_user_id_users_id_fk" FOREIGN KEY ("user_id") REFERENCES "public"."users"("id") ON DELETE cascade ON UPDATE no action;

apps/backend/drizzle/meta/0000_snapshot.json

@@ -0,0 +1,141 @@
+{
+  "id": "ccda4e45-b486-4477-892a-b4ff308b3326",
+  "prevId": "00000000-0000-0000-0000-000000000000",
+  "version": "7",
+  "dialect": "postgresql",
+  "tables": {
+    "public.users": {
+      "name": "users",
+      "schema": "",
+      "columns": {
+        "id": {
+          "name": "id",
+          "type": "uuid",
+          "primaryKey": true,
+          "notNull": true,
+          "default": "gen_random_uuid()"
+        },
+        "username": {
+          "name": "username",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "avatar_url": {
+          "name": "avatar_url",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": false
+        },
+        "created_at": {
+          "name": "created_at",
+          "type": "timestamp",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "now()"
+        },
+        "updated_at": {
+          "name": "updated_at",
+          "type": "timestamp",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "now()"
+        }
+      },
+      "indexes": {},
+      "foreignKeys": {},
+      "compositePrimaryKeys": {},
+      "uniqueConstraints": {
+        "users_username_unique": {
+          "name": "users_username_unique",
+          "nullsNotDistinct": false,
+          "columns": [
+            "username"
+          ]
+        }
+      },
+      "policies": {},
+      "checkConstraints": {},
+      "isRLSEnabled": false
+    },
+    "public.wallets": {
+      "name": "wallets",
+      "schema": "",
+      "columns": {
+        "id": {
+          "name": "id",
+          "type": "uuid",
+          "primaryKey": true,
+          "notNull": true,
+          "default": "gen_random_uuid()"
+        },
+        "user_id": {
+          "name": "user_id",
+          "type": "uuid",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "address": {
+          "name": "address",
+          "type": "text",
+          "primaryKey": false,
+          "notNull": true
+        },
+        "is_primary": {
+          "name": "is_primary",
+          "type": "boolean",
+          "primaryKey": false,
+          "notNull": true,
+          "default": false
+        },
+        "created_at": {
+          "name": "created_at",
+          "type": "timestamp",
+          "primaryKey": false,
+          "notNull": true,
+          "default": "now()"
+        }
+      },
+      "indexes": {},
+      "foreignKeys": {
+        "wallets_user_id_users_id_fk": {
+          "name": "wallets_user_id_users_id_fk",
+          "tableFrom": "wallets",
+          "tableTo": "users",
+          "columnsFrom": [
+            "user_id"
+          ],
+          "columnsTo": [
+            "id"
+          ],
+          "onDelete": "cascade",
+          "onUpdate": "no action"
+        }
+      },
+      "compositePrimaryKeys": {},
+      "uniqueConstraints": {
+        "wallets_address_unique": {
+          "name": "wallets_address_unique",
+          "nullsNotDistinct": false,
+          "columns": [
+            "address"
+          ]
+        }
+      },
+      "policies": {},
+      "checkConstraints": {},
+      "isRLSEnabled": false
+    }
+  },
+  "enums": {},
+  "schemas": {},
+  "sequences": {},
+  "roles": {},
+  "policies": {},
+  "views": {},
+  "_meta": {
+    "columns": {},
+    "schemas": {},
+    "tables": {}
+  }
+}

apps/backend/drizzle/meta/_journal.json

@@ -0,0 +1,13 @@
+{
+  "version": "7",
+  "dialect": "postgresql",
+  "entries": [
+    {
+      "idx": 0,
+      "version": "7",
+      "when": 1778589700461,
+      "tag": "0000_init",
+      "breakpoints": true
+    }
+  ]
+}

apps/backend/package.json

@@ -8,7 +8,11 @@
     "test": "echo \"Error: no test specified\" && exit 1",
     "dev": "tsx watch src/index.ts",
     "build": "tsc",
-    "start": "node dist/index.js"
+    "start": "node dist/index.js",
+    "db:generate": "drizzle-kit generate",
+    "db:migrate": "drizzle-kit migrate",
+    "db:push": "drizzle-kit push",
+    "db:studio": "drizzle-kit studio"
   },
   "keywords": [],
   "author": "",
@@ -17,15 +21,18 @@
   "dependencies": {
     "cors": "^2.8.6",
     "dotenv": "^17.3.1",
+    "drizzle-orm": "^0.45.2",
     "express": "^5.2.1",
     "morgan": "^1.10.1",
+    "postgres": "^3.4.9",
     "socket.io": "^4.8.3"
   },
   "devDependencies": {
     "@types/cors": "^2.8.19",
     "@types/express": "^5.0.6",
     "@types/morgan": "^1.9.10",
     "@types/node": "^20.19.37",
+    "drizzle-kit": "^0.31.10",
     "ts-node": "^10.9.2",
     "tsx": "^4.21.0",
     "typescript": "^5.9.3"

apps/backend/src/db/index.ts

@@ -0,0 +1,13 @@
+import postgres from 'postgres';
+import { drizzle } from 'drizzle-orm/postgres-js';
+import * as schema from './schema.js';
+
+const connectionString = process.env['DATABASE_URL'];
+
+if (!connectionString) {
+  throw new Error('DATABASE_URL is not set');
+}
+
+const client = postgres(connectionString);
+
+export const db = drizzle(client, { schema });

apps/backend/src/db/schema.ts

@@ -0,0 +1,24 @@
+import { pgTable, text, timestamp, uuid, boolean } from 'drizzle-orm/pg-core';
+
+export const users = pgTable('users', {
+  id: uuid('id').primaryKey().defaultRandom(),
+  username: text('username').unique(),
+  avatarUrl: text('avatar_url'),
+  createdAt: timestamp('created_at').notNull().defaultNow(),
+  updatedAt: timestamp('updated_at').notNull().defaultNow(),
+});
+
+export const wallets = pgTable('wallets', {
+  id: uuid('id').primaryKey().defaultRandom(),
+  userId: uuid('user_id')
+    .notNull()
+    .references(() => users.id, { onDelete: 'cascade' }),
+  address: text('address').notNull().unique(),
+  isPrimary: boolean('is_primary').notNull().default(false),
+  createdAt: timestamp('created_at').notNull().defaultNow(),
+});
+
+export type User = typeof users.$inferSelect;
+export type NewUser = typeof users.$inferInsert;
+export type Wallet = typeof wallets.$inferSelect;
+export type NewWallet = typeof wallets.$inferInsert;

apps/backend/src/index.ts

@@ -4,6 +4,8 @@ import dotenv from 'dotenv';
 import { createServer } from 'http';
 import { Server } from 'socket.io';
 import morgan from 'morgan';
+import { db } from './db/index.js';
+import { sql } from 'drizzle-orm';
 
 dotenv.config();
 
@@ -17,8 +19,13 @@ app.use(cors());
 app.use(express.json());
 app.use(morgan('dev'));
 
-app.get('/health', (req, res) => {
-  res.json({ status: 'ok' });
+app.get('/health', async (_req, res) => {
+  try {
+    await db.execute(sql`SELECT 1`);
+    res.json({ status: 'ok', db: 'connected' });
+  } catch {
+    res.status(503).json({ status: 'error', db: 'unreachable' });
+  }
 });
 
 io.on('connection', (socket) => {