title: MongoError: Invalid Operation, No operations in bulk
body: <p>I'm unable to do bulk insert to mongo using mongoose.</p>
  
  <pre><code>var mongoose = require('mongoose');
  var Schema = mongoose.Schema;
  
  // Define our results schema
  var webSchema = new Schema({"abc" : String},{
    collection: 'web_v2'
  });
  
  MyApi.prototype.Webs= mongoose.model('Webs', webSchema);
  
  resultData = [{"abc": "12121221"},{"abc": "44545"},{"abc": "545"}]
  
  MyApi.prototype.Webs.collection.insert(resultData, function (err, myDocuments) {
    if (err) {
      console.log(err);
    } else {
      console.log("web inserted : " + myDocuments.result.n);
    }
  });
  </code></pre>
  
  <p>I'm getting the following error</p>
  
  <pre><code>MongoError: Invalid Operation, No operations in bulk
  at Function.MongoError.create (/pathtoapp/node_modules/mongoose/node_modules/mongodb/node_modules/mongodb-core/lib/error.js:31:11)
  at toError (/pathtoapp/node_modules/mongoose/node_modules/mongodb/lib/utils.js:114:22)
  at OrderedBulkOperation.execute (/pathtoapp/node_modules/mongoose/node_modules/mongodb/lib/bulk/ordered.js:500:11)
  at bulkWrite (/pathtoapp/node_modules/mongoose/node_modules/mongodb/lib/collection.js:582:8)
  at Collection.insertMany (/pathtoapp/node_modules/mongoose/node_modules/mongodb/lib/collection.js:477:44)
  at Collection.insert (/pathtoapp/node_modules/mongoose/node_modules/mongodb/lib/collection.js:753:15)
  at NativeCollection.(anonymous function) as insert (/pathtoapp/node_modules/mongoose/lib/drivers/node-mongodb-native/collection.js:136:28)
  at /pathtoapp/index.js:481:57
  at /pathtoapp/node_modules/async/lib/async.js:721:13
  at /pathtoapp/node_modules/async/lib/async.js:52:16
  at async.forEachOf.async.eachOf (/pathtoapp/node_modules/async/lib/async.js:236:30)
  at _parallel (/pathtoapp/node_modules/async/lib/async.js:712:9)
  at Object.async.parallel (/pathtoapp/node_modules/async/lib/async.js:726:9)
  at /pathtoapp/index.js:479:43
  at /pathtoapp/node_modules/async/lib/async.js:721:13
  at /pathtoapp/node_modules/async/lib/async.js:52:16
  </code></pre>
  
  <p>anyone please let me know what am i doing wrong.?</p>