Add TypeORM DB and Resources (#2)

Co-authored-by: Joe Arndt <jmarndt@users.noreply.github.com>
Reviewed-on: #2

src/merchants/merchants.service.ts

@@ -0,0 +1,35 @@
+import { Injectable } from '@nestjs/common';
+import { CreateMerchantDto } from './dto/create-merchant.dto';
+import { UpdateMerchantDto } from './dto/update-merchant.dto';
+import { MerchantDataService } from './merchant-data.service';
+import { Merchant } from './entities/merchant.entity';
+
+@Injectable()
+export class MerchantsService {
+  public constructor(private merchantDataService: MerchantDataService) { }
+
+  public async findAll(): Promise<Merchant[]> {
+    return await this.merchantDataService.getAll();
+  }
+
+  public async findById(id: string): Promise<Merchant> {
+    const merchant = await this.merchantDataService.getById(id);
+    if (!merchant) {
+      throw new Error('Merchant not found.');
+    }
+
+    return merchant;
+  }
+
+  public async create(merchant: CreateMerchantDto): Promise<Merchant> {
+    return await this.merchantDataService.create(merchant.name);
+  }
+
+  public async update(merchant: UpdateMerchantDto): Promise<Merchant> {
+    return await this.merchantDataService.update(merchant);
+  }
+
+  public async remove(id: string): Promise<void> {
+    await this.merchantDataService.delete(id);
+  }
+}