title: linker command failed in react native app, using react-native-firebase
body: <p>I developed a react native app using react-native-firebase library.
  I want to set my app icon, so I used this library:<code>npm install -g yo generator-rn-toolbox</code> from <a href="https://blog.bam.tech/developper-news/change-your-react-native-app-icons-in-a-single-command-line" rel="noreferrer">here</a>.</p>
  
  <p>When I try to build the project I receive this error:</p>
  
  <p><code>Undefined symbols for architecture arm64:
    "_OBJC_CLASS_$_RCTSRWebSocket", referenced from:
        objc-class-ref in libReact.a(RCTInspectorPackagerConnection.o)
    "_OBJC_CLASS_$_RCTReconnectingWebSocket", referenced from:
        objc-class-ref in libReact.a(RCTPackagerConnection.o)
  ld: symbol(s) not found for architecture arm64
  clang: error: linker command failed with exit code 1 (use -v to see invocation)
  </code>
  How do I fix this ?</p>