old_contents: import { StackNavigator, TabNavigator } from 'react-navigation';
  
  import DeveloperScreen from './components/developer/developer-screen';
  import HomeScreen from './components/home/home-screen';
  import SampleScreen from './components/developer/sample-screen';
  
  // The home tab holding screens in a stack.
  const HomeTab = StackNavigator({
    HomeScreen: {
      screen: HomeScreen,
    },
  });
  
  // The developer tab holding screens in a stack.
  const DeveloperTab = StackNavigator({
    DeveloperScreen: {
      screen: DeveloperScreen,
    },
    SampleScreen: {
      screen: SampleScreen,
    },
  });
  
  // Main navigation. Contains different tabs.
  const AppNavigator = TabNavigator({
    HomeTab: {
      screen: HomeTab,
    },
    DeveloperTab: {
      screen: DeveloperTab,
    },
  }, {
    tabBarPosition: 'bottom',
    tabBarOptions: {
      activeTintColor: '#e91e63',
    },
  });
  
  export default AppNavigator;
  
new_contents: import { StackNavigator, TabNavigator } from 'react-navigation';
  
  import DeveloperScreen from './components/developer/developer-screen';
  import HomeScreen from './components/home/home-screen';
  import SampleScreen from './components/developer/sample-screen';
  import CreateJobScreen from './components/developer/create-job-screen';
  
  // The home tab holding screens in a stack.
  const HomeTab = StackNavigator({
    HomeScreen: {
      screen: HomeScreen,
    },
  });
  
  // The developer tab holding screens in a stack.
  const DeveloperTab = StackNavigator({
    DeveloperScreen: {
      screen: DeveloperScreen,
    },
    SampleScreen: {
      screen: SampleScreen,
    },
    CreateJobScreen: {
      screen: CreateJobScreen,
    },
  });
  
  // Main navigation. Contains different tabs.
  const AppNavigator = TabNavigator({
    HomeTab: {
      screen: HomeTab,
    },
    DeveloperTab: {
      screen: DeveloperTab,
    },
  }, {
    tabBarPosition: 'bottom',
    tabBarOptions: {
      activeTintColor: '#e91e63',
    },
  });
  
  export default AppNavigator;
  
subject: Add create job screen to appNavigator