title: Using component from another module in Angular 4
body: <p>I have RoomsComponent in the AppModule, its route is /rooms. 
  Also i have a lazy-loaded module CompaniesModule with component CompaniesComponent with the route /companies.</p>
  
  <p>I'm trying to build a route like /companies/{company_id}/rooms/ when RoomsComponent is reused from AppModule. </p>
  
  <p>I can't do it a long RoomsComponent is not declared in the CompaniesModule, but this throws me an error, because a component cannot be declared in multiple modules.</p>