feat: initial prototype works

I can log in and create a book! Woo!

api/src/app/services/auth.service.ts

@@ -1,13 +1,11 @@
 import { FastifyInstance } from "fastify";
 import { JwtPayload, User } from "@library/shared-types";
-import { PrismaClient } from "../../generated/prisma";
+import { prisma } from "../lib/prisma";
 
 export class AuthService {
-  private prisma: PrismaClient;
+  private prisma = prisma;
 
-  constructor(private readonly app: FastifyInstance) {
-    this.prisma = new PrismaClient();
-  }
+  constructor(private readonly app: FastifyInstance) {}
 
   /**
    * Generate JWT token for user.