add error-landing-page aka 404

src/app/app.module.ts

@@ -5,11 +5,13 @@ import { NgModule } from '@angular/core';
 import { AppComponent } from './app.component';
 import { BrowserAnimationsModule } from '@angular/platform-browser/animations';
 import { AppRoutingModule } from './/app-routing.module';
+import { ErrorLandingPageComponent } from './error-landing-page/error-landing-page.component';
 
 
 @NgModule({
   declarations: [
-    AppComponent
+    AppComponent,
+    ErrorLandingPageComponent
   ],
   imports: [
     BrowserModule,

src/app/error-landing-page/error-landing-page.component.html

+<p>
+  error-landing-page works!
+</p>

src/app/error-landing-page/error-landing-page.component.spec.ts

+import { async, ComponentFixture, TestBed } from '@angular/core/testing';
+
+import { ErrorLandingPageComponent } from './error-landing-page.component';
+
+describe('ErrorLandingPageComponent', () => {
+  let component: ErrorLandingPageComponent;
+  let fixture: ComponentFixture<ErrorLandingPageComponent>;
+
+  beforeEach(async(() => {
+    TestBed.configureTestingModule({
+      declarations: [ ErrorLandingPageComponent ]
+    })
+    .compileComponents();
+  }));
+
+  beforeEach(() => {
+    fixture = TestBed.createComponent(ErrorLandingPageComponent);
+    component = fixture.componentInstance;
+    fixture.detectChanges();
+  });
+
+  it('should create', () => {
+    expect(component).toBeTruthy();
+  });
+});

src/app/error-landing-page/error-landing-page.component.ts

+import { Component, OnInit } from '@angular/core';
+
+@Component({
+  selector: 'app-error-landing-page',
+  templateUrl: './error-landing-page.component.html',
+  styleUrls: ['./error-landing-page.component.scss']
+})
+export class ErrorLandingPageComponent implements OnInit {
+
+  constructor() { }
+
+  ngOnInit() {
+  }
+
+}