title: Can't find variable: tab in React Native's react-native-material-bottom-navigation
body: <p>I have got react-native-material-bottom-navigation library for my project (which is blank by the way). I have used exactly the same code as in the example at <a href="https://github.com/timomeh/react-native-material-bottom-navigation" rel="nofollow noreferrer">https://github.com/timomeh/react-native-material-bottom-navigation</a> , line by line, but I get the following error :</p>
  
  <pre><code>ReferenceError: Can't find variable: tab
  
   This error is located at:
     in FullTab (at App.js:53)
     in TouchableWithoutFeedback (at TabList.js:165)
     in RCTView (at View.js:43)
     in TabList (at BottomNavigation.js:134)
     in PressFeedback (at BottomNavigation.js:132)
     in BackgroundDecorator (at BottomNavigation.js:130)
     in RCTView (at View.js:43)
     ...
  </code></pre>
  
  <p>The code from line 53 is </p>
  
  <pre><code> &lt;FullTab
    isActive={isActive}
    key={tab.key}
    label={tab.label}
    renderIcon={this.renderIcon(tab.icon)}
  /&gt;
  </code></pre>
  
  <p>Why am I getting this error?</p>