app.module.ts

@NgModule({
  declarations: [ AppComponent, TodoListComponent, TodoDialog ],
  imports: [
    BrowserModule,
    BrowserAnimationsModule,
    ReactiveFormsModule,
    RouterModule.forRoot([{path: '', component: TodoListComponent}]),
    MatListModule,
    MatButtonModule,
    MatCardModule,
    MatDialogModule,
    MatFormFieldModule,
    MatTooltipModule,
    FlexModule,
    MatInputModule,
    MatSelectModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule {}