Why is the "Create Pull Request" menu item in Visual Studio 2015 always disabled?
<p>No matter what I try, this menu item never seems to "enable":</p>

<p><a href="https://i.stack.imgur.com/y37hz.png" rel="noreferrer"><img src="https://i.stack.imgur.com/y37hz.png" alt="enter image description here"></a></p>

<p>What am I missing?  This is in VS 2015 Update1 pointed at a Git repo on TFS 2015.</p>