title: Cannot determine the module for class X in X.ts! Add X to the NgModule to fix it error in ionic2
body: <p>I am facing an issue when I try to build my app using the following command :</p>
  
  <p><code>ionic cordova run android --prod --release</code></p>
  
  <p>Everything runs fine if I run the command as below:</p>
  
  <pre><code>ionic cordova run android
  </code></pre>
  
  <p>The error Iam getting is :</p>
  
  <blockquote>
    <p>Error: Cannot determine the module for class CartItemsPage in
    C:/test/src/pages/cart/cart-items.ts! Add CartItemsPage to the
    NgModule to fix it. Cannot determine the module for class ItemsPage in
    C:/test/src/pages/items/items.ts! Add ItemsPage to th e NgModule to
    fix it. Cannot determine the module for class UserHomePage in
    C:/test/src/pages/user-home/user-home.ts! Add User HomePage to the
    NgModule to fix it. Cannot determine the module for class
    ForgotPasswordPage in C:/test/src/pages/forgot-password/forgot-pas
    sword.ts! Add ForgotPasswordPage to the NgModule to fix it. Cannot
    determine the module for class LoginPage in
    C:/test/src/pages/login/login.ts! Add LoginPage to th e NgModule to
    fix it. Cannot determine the module for class SignupPage in
    C:/test/src/pages/signup/signup.ts! Add SignupPage t o the NgModule to
    fix it. Cannot determine the module for class WelcomePage in
    C:/test/src/pages/welcome/welcome.ts! Add WelcomePa ge to the NgModule
    to fix it. Cannot determine the module for class PincodePage in
    C:/test/src/pages/pincode/pincode.ts! Add PincodePa ge to the NgModule
    to fix it. Cannot determine the module for class AppHomePage in
    C:/test/src/pages/app-home/app-home.ts! Add AppHome Page to the
    NgModule to fix it. Cannot determine the module for class ProfilePage
    in C:/test/src/pages/profile/profile.ts! Add ProfilePa ge to the
    NgModule to fix it. Cannot determine the module for class
    OrderDetailPage in C:/test/src/pages/myorders/order-detail.ts! Add 
    OrderDetailPage to the NgModule to fix it. Cannot determine the module
    for class MyOrdersPage in C:/test/src/pages/myorders/myorders.ts! Add
    MyOrde rsPage to the NgModule to fix it. Cannot determine the module
    for class LogoutPage in C:/test/src/pages/logout/logout.ts! Add
    LogoutPage t o the NgModule to fix it. Cannot determine the module for
    class MyApp in C:/test/src/app/app.component.ts! Add MyApp to the
    NgModu le to fix it. Cannot determine the module for class
    RemoveUnderscorePipe in C:/test/src/utils/pipes/RemoveUnderscore.t s!
    Add RemoveUnderscorePipe to the NgModule to fix it.</p>
  </blockquote>
  
  <p>but I have added all my pages and pipes to app.module.ts as below :</p>
  
  <pre><code>// Imports
  
  // The translate loader needs to know where to load i18n files
  // in Ionic's static asset pipeline.
  export function HttpLoaderFactory(http: Http) {
    return new TranslateHttpLoader(http, './assets/i18n/', '.json');
  }
  
  
  let pages:any = [
    MyApp,
    LoginPage,
    UserHomePage,
    SignupPage,
    AppHomePage,
    WelcomePage,
    ItemsPage,
    CartItemsPage,
    ProfilePage,
    MyOrdersPage,
    OrderDetailPage,
    ForgotPasswordPage,
    PincodePage,
    LogoutPage
  ];
  
  let pipes = [RemoveUnderscorePipe];
  
  export function declarations() {
    return pages.concat(pipes);
  }
  
  export function entryComponents() {
    return pages;
  }
  
  export function providers() {
    return [
      Api,
      ItemsService,
      UserService,
      ToastService,
      CartService,
      OrdersService,
      TokenService,
      Camera,
      GoogleMaps,
      SplashScreen,
      StatusBar,
  
      // Keep this to enable Ionic's runtime error handling during development
      {provide: ErrorHandler, useClass: IonicErrorHandler}
    ];
  }
  
  
  @NgModule({
    declarations: declarations(),
    imports: [
      BrowserModule,
      HttpModule,
      TranslateModule.forRoot({
        loader: {
          provide: TranslateLoader,
          useFactory: HttpLoaderFactory,
          deps: [Http]
        }
      }),
      IonicModule.forRoot(MyApp),
      IonicStorageModule.forRoot()
    ],
    bootstrap: [IonicApp],
    entryComponents: entryComponents(),
    providers: providers()
  })
  export class AppModule {
  }
  </code></pre>
  
  <p>If u see my app.module.ts, I have added components and pipes to entrycomponents and declarations. Is there anything I am missing for production flag.
  How can I resolve this issue?</p>