title: TextInput underline color for ios in react-native
body: <p>i am doing mobile applications in react-native for android and ios.
  In my project i am using TextInput Component(ios). This component appear without underline. How to use TextInput with underline color in ios.     </p>
  
  <p>code sample -</p>
  
  <pre><code>&lt;TextInput
   ref={'cardbatch1'}                 
   keyboardType = 'numeric'
   placeholder = 'Batch Number'
   autoCapitalize = 'none'                                                    
  /&gt;
  </code></pre>