feat(db): add Prisma schema and global PrismaModule

prisma/prisma.service.ts

@@ -0,0 +1,20 @@
+import { Injectable, OnModuleDestroy, OnModuleInit } from '@nestjs/common';
+import { PrismaClient } from './generated/client';
+import { PrismaPg } from '@prisma/adapter-pg';
+
+/** Prisma client shared by the whole app (global PrismaModule), connected to `DATABASE_URL` through the pg driver adapter. */
+@Injectable()
+export class PrismaService extends PrismaClient implements OnModuleInit, OnModuleDestroy {
+  constructor() {
+    const adapter = new PrismaPg({ connectionString: process.env.DATABASE_URL });
+    super({ adapter });
+  }
+
+  async onModuleInit() {
+    await this.$connect();
+  }
+
+  async onModuleDestroy() {
+    await this.$disconnect();
+  }
+}