title: Git Windows Client denies me permission to Sync/push changes to my own repository
body: <p>I have two repositories, one that I created, and one that I forked from ocotocat/Spoon-Knife.  I can push commits to the first, but not to Spoon-Knife.</p>
  
  <p>I forked ocotocat/Spoon-Knife, then cloned it to my desktop, then edited one file, then committed, and on Sync (push), it fails with "It seems you do not have permissions to push to this repository".</p>
  
  <p>I tried to add myself as a collaborator, but it says "cannot own owner as a collaborator" so I am pretty sure I should have permission.  As an owner.</p>
  
  <p>How do I push these changes using the GitHub Windows client v 2.13.2.4?  </p>