title: How to make a pull request to Visual Studio Online
body: <p>I use Visual Studio Online (VSO), and few days ago the VSO team announced support of pull requests. </p>
  
  <p>I would like to ask, is it possible to forbid commits without a pull request from Visual Studio 2013?</p>
  
  <p>I mean, that I want forbid my team to commit changes, until they pull request first, to allow the repository owners to accept or decline changes.</p>