title: Add new item in nested array
body: <p>I need to update an embedded Fields array through Mongo console. I need to add a new item as "Test13" with default value as "1" in all the <code>Fields</code> subdocuments.</p>
  
  <p>Here is a sample of my collection with name <code>testmarket</code>:</p>
  
  <pre><code>{ 
      "_id" : ObjectId("573c9801056848fef667bfde"), 
      "MST" : "RR", 
      "GST" : null, 
      "Fields" : [{
          "Test1" : "boolean", 
          "Test2" : "TestLot", 
          "Test3" : "TestLot", 
          "Test4" : null, 
          "Test5" : true, 
          "Test6" : true, 
          "Test7" : NumberInt(1), 
          "Test8" : false, 
          "Test9" : false, 
          "Test10" : false, 
          "Test11" : false, 
          "Test12" : null
       }, {
          "Test1" : "String", 
          "Test2" : "TestSerial", 
          "Test3" : "TestSerial", 
          "Test4" : null, 
          "Test5" : true, 
          "Test6" : true, 
          "Test7" : NumberInt(1), 
          "Test8" : false, 
          "Test9" : false, 
          "Test10" : false, 
          "Test11" : false, 
          "Test12" : null
      }]
  }
  </code></pre>
  
  <p>Collection is very big and I need to add a new item in Fields collection. </p>
  
  <p>I have tried running the query</p>
  
  <pre><code>db.testmarket.Fields.update(
      {}, 
      {$set : {"Test13":"1"}}, 
      {upsert:true, multi:true}
  ) 
  </code></pre>