Stubs out Diagram component.

src/app/app.module.ts

@@ -3,10 +3,12 @@ import { NgModule } from '@angular/core';
 
 import { AppRoutingModule } from './app-routing.module';
 import { AppComponent } from './app.component';
+import { DiagramComponent } from './diagram/diagram.component';
 
 @NgModule({
   declarations: [
-    AppComponent
+    AppComponent,
+    DiagramComponent
   ],
   imports: [
     BrowserModule,

src/app/diagram/diagram.component.html

@@ -0,0 +1 @@
+<p>diagram works!</p>

src/app/diagram/diagram.component.spec.ts

@@ -0,0 +1,25 @@
+import { async, ComponentFixture, TestBed } from '@angular/core/testing';
+
+import { DiagramComponent } from './diagram.component';
+
+describe('DiagramComponent', () => {
+  let component: DiagramComponent;
+  let fixture: ComponentFixture<DiagramComponent>;
+
+  beforeEach(async(() => {
+    TestBed.configureTestingModule({
+      declarations: [ DiagramComponent ]
+    })
+    .compileComponents();
+  }));
+
+  beforeEach(() => {
+    fixture = TestBed.createComponent(DiagramComponent);
+    component = fixture.componentInstance;
+    fixture.detectChanges();
+  });
+
+  it('should create', () => {
+    expect(component).toBeTruthy();
+  });
+});

src/app/diagram/diagram.component.ts

@@ -0,0 +1,15 @@
+import { Component, OnInit } from '@angular/core';
+
+@Component({
+  selector: 'app-diagram',
+  templateUrl: './diagram.component.html',
+  styleUrls: ['./diagram.component.scss']
+})
+export class DiagramComponent implements OnInit {
+
+  constructor() { }
+
+  ngOnInit() {
+  }
+
+}