title: Cannot read property 'ObjectId' of undefined at Stream.GridWriteStream
body: <p>I am getting this error - Cannot read property 'ObjectId' of undefined at Stream.GridWriteStream at gfs.createWriteStream. Funny things is my implementation was working fine till yesterday. I cannot figure out what went wrong.</p>
  
  <pre><code>var Grid = require('gridfs-stream');
  
  Grid.mongo = mongoose.mongo;
  var gfs;
  
  var mongoose = require('mongoose');
      mongoose.connect('mongodb://user:pass@example.com:15879/thing', function (error) {
          if (error) {
              console.log(error);
          }
      });
  
  var conn = mongoose.connection;
  conn.once('open', function callback(){
    gfs = Grid(conn.db);
    var writestream = gfs.createWriteStream({
      filename: "secure"
    });
  });
  </code></pre>