Updating the Workout Builder module

Now, let's update WorkoutBuilderModule.  First, add the following import to the file:

import { WorkoutBuilderRoutingModule } from './workout-builder-routing.module';

It imports the child routing that we just set up. Next, update the @NgModule decorator to add workoutBuilderRoutingModule:

...
@NgModule({
  imports: [
    CommonModule,
    WorkoutBuilderRoutingModule
  ],
...
}) 

Finally, add the imports and declarations for the new navigation components that can be found in checkpoint4.2:

import { LeftNavExercisesComponent } from './navigation/left-nav-exercises.component';
import { LeftNavMainComponent } from './navigation/left-nav-main.component';
import { SubNavMainComponent } from './navigation/sub-nav-main.component';
...
  declarations: [
    ...
    LeftNavExercisesComponent,
    LeftNavMainComponent,
    SubNavMainComponent]