No Firebase App '[DEFAULT]' has been created

This is my ionic info:

Cordova CLI: 6.3.1
Ionic Framework Version: 2.0.0-rc.1
Ionic CLI Version: 2.1.1
Ionic App Lib Version: 2.1.1
Ionic App Scripts Version: 0.0.36
OS: Distributor ID: Ubuntu Description: Ubuntu 16.04.1 LTS
Node Version: v4.2.6

I’m updating from beta version to RC and I’m using Firebase v. 3.5.0.
Everytime I do ionic serve I get this error: ORIGINAL EXCEPTION: No Firebase App '[DEFAULT]' has been created - call Firebase App.initializeApp().

my app.module.ts looks like this:

import { NgModule } from ‘@angular/core’;
import { IonicApp, IonicModule } from ‘ionic-angular’;
import { HomePage } from ‘…/pages/home/home’;
… other page imports

@NgModule({
declarations: [
MyApp,
HomePage,
… other stuff
],
imports: [
IonicModule.forRoot(MyApp)
],
bootstrap: [IonicApp],
entryComponents: [
MyApp,
HomePage,
… other pages
],
providers: [… some providers]
})
export class AppModule {}

my app.component.ts:

import firebase from 'firebase';
import { Component } from '@angular/core';
import { Platform } from 'ionic-angular';
import { StatusBar } from 'ionic-native';
import { HomePage } from '../pages/home/home';

@Component({
  template: `<ion-nav [root]="rootPage"></ion-nav>`
})
export class MyApp {

  rootPage = HomePage;

  constructor(platform: Platform) {
    platform.ready().then(() => {

      var config = {
        apiKey: "........",
        authDomain: "......",
        databaseURL: ".......",
        storageBucket: ".......",
        messagingSenderId: "......"
      };

      firebase.initializeApp(config);
      StatusBar.styleDefault();
    });
  }
}

Hey!

Check this out: https://github.com/javebratt/event-tutorial/blob/master/src/app/app.component.ts