title: REBUILD/regenerate ios and android folders
body: <p>How can I rebuild my ios and android folders if I deleted them?
  I tried to use 1: "react-native upgrade" 2: "react-native-git-upgrade"</p>
  
  <p>1: This one makes just empty/blank .xcodeproj like first one. 
  2. This doesn't generate xcodeproj at all.</p>