Feature: Added the customer module to list / edit customers. This is needed to add the customer discount functionality

bookie/src/app/customers/customer-list-resolver.service.ts

@@ -0,0 +1,18 @@
+import { Injectable } from '@angular/core';
+import { Resolve } from '@angular/router';
+import { Observable } from 'rxjs/internal/Observable';
+
+import { Customer } from '../core/customer';
+
+import { CustomerService } from './customer.service';
+
+@Injectable({
+  providedIn: 'root',
+})
+export class CustomerListResolver implements Resolve<Customer[]> {
+  constructor(private ser: CustomerService) {}
+
+  resolve(): Observable<Customer[]> {
+    return this.ser.list();
+  }
+}