title: Requiring unknown module "crypto" in react-native environment
body: <p>I'm writing a simple Twitter app using react-native. Using <a href="https://github.com/ttezel/twit" rel="noreferrer">twit</a> module to get twitter feeds and stream. Below is the code, it works fine node. However, when included into my react-native app, seeing error "Requiring unknown module "crypto"". Dependency seems to be myapp->twit->oauth->crypto (thats part of node v0.12.2). Any suggestions to get this working inside react-native environment?</p>
  
  <pre><code>var Twit = require('twit')
  var T = new Twit({
      consumer_key:''
    , consumer_secret:''
    , access_token:''
    , access_token_secret:''
  })
  var filtered_tweets=[];
  var error;
  var isSuccess=false;
  
  function getTweets(searchString){
      T.get('search/tweets',{q:searchString, count:100}, getResponse);
      }
  
  function getResponse(err,data,response){
          if(err) { 
              handleGetErr(err); 
          }
          handleGetData(data.statuses);
      }
  
  function handleGetErr(err){
  
      enter code here
  
      error = err;
      }
  
  function handleGetData(data){
      data.map(function(tweet){
        var twit={
          twit:tweet.id,
          created_at:tweet.created_at,
          text:tweet.text,
          retweet_count:tweet.retweet_count,
          favorite_count:tweet.favorite_count
        };
        filtered_tweets.push(twit);
      });
      console.log(filtered_tweets);
      isSuccess=true;
  }
  getTweets("@sahaswaranamam");
  module.exports = getTweets;
  </code></pre>
  
  <p>![attached][2]</p>