title: Unable to resolve module 'react-navigation'
body: <p>Here is the error I get:</p>
  
  <p><a href="https://i.stack.imgur.com/yCNdw.png" rel="noreferrer"><img src="https://i.stack.imgur.com/yCNdw.png" alt="Error"></a></p>
  
  <p><strong>package.json</strong></p>
  
  <pre><code>{
    "name": "LoginApp2",
    "version": "0.0.1",
    "private": true,
    "scripts": {
      "start": "node node_modules/react-native/local-cli/cli.js start",
      "test": "jest"
    },
    "dependencies": {
      "react": "16.0.0-alpha.12",
      "react-native": "0.48.3"
    },
    "devDependencies": {
      "babel-jest": "21.2.0",
      "babel-preset-react-native": "4.0.0",
      "jest": "21.2.1",
      "react-test-renderer": "16.0.0-alpha.12"
    },
    "jest": {
      "preset": "react-native"
    }
  }
  </code></pre>
  
  <p><strong>index.js</strong></p>
  
  <pre><code>  import React, { Component } from 'react';
  import { AppRegistry,View,Text,StyleSheet } from 'react-native';
  
  import UsersManager from './pages/app';
  AppRegistry.registerComponent('LoginApp2', () =&gt; UsersManager);
  </code></pre>
  
  <p><strong>pages/app.js</strong></p>
  
  <pre><code>import React, { Component } from 'react';
  import { AppRegistry,View,Text,StyleSheet,ScrollView,TouchableOpacity } from 'react-native';
  import { StackNavigator } from 'react-navigation';
  
  import HomeScreen from './home';
  import Login from './login';
  import Register from './register';
  import Profile from './profile';
  
  const UsersManager = StackNavigator({
  Home: { screen: HomeScreen },
  Login: { screen: Login },
  Register: {screen: Register},
  Profile: {screen: Profile}
  
  });
  export default UsersManager;
  </code></pre>
  
  <p>Can someone please help me solve this issue?</p>