title: Unrecognized command 'run-eject'
body: <p>I want to eject my react-native so I can install mobx but running both 'yarn run eject' and 'npm run eject' doesn't work.i think this is new issue and so couldn't find help online. any help would be appreciated. 
  this is my package.json file and the error given below<a href="https://i.stack.imgur.com/PY5Vb.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/PY5Vb.png" alt="Here is the photo"></a>.</p>
  
  <pre><code>{
    "name": "a2x",
    "version": "0.1.0",
    "private": true,
    "devDependencies": {
      "babel-preset-react-native-stage-0": "^1.0.1",
      "jest": "^22.4.4",
      "jest-react-native": "^18.0.0",
      "react-test-renderer": "16.3.1"
    },
    "scripts": {
      "start": "react-native start",
      "android": "react-native run-android",
      "ios": "react-native run-ios",
      "test": "jest",
      "eject": "react-native run-eject"
    },
    "jest": {
      "preset": "react-native"
    },
    "dependencies": {
      "axios": "^0.18.0",
      "mobx": "^5.5.0",
      "mobx-react": "^5.2.8",
      "react": "16.3.1",
      "react-native": "~0.55.2",
      "react-native-elements": "^0.19.1",
      "react-navigation": "^2.0.1"
    }
  }
  </code></pre>