title: transaction.autocommit in django 1.7
body: <p>Can someone please tell me what does transaction.autocommit() do?</p>
  
  <p>What is the difference between the following code snippets?</p>
  
  <pre><code>model_object.save()
  </code></pre>
  
  <p></p>
  
  <pre><code>with transaction.autocommit():
       model_object.save()
  </code></pre>
  
  <p></p>
  
  <pre><code>with transaction.autocommit():
       model_object.save()
  
          with transaction.autocommit():
               model2_object.save()
  
       model3_object.save()
  </code></pre>
  
  <p>Also, do we need transaction.autocommit() in Django 1.7? As long as I understand Django does db operations in autocommit mode only. Please correct me if I am wrong</p>