title: GitHub for Mac crashes on open because of local repository issue
body: <p>I am trying to figure out why my GitHub for Mac crashes on start when I choose a local repository. I added this local repository from a folder I had cloned. Unfortunately, I was playing around with the git command line and I must have done something to corrupt the local repository.</p>
  
  <p>Now my GitHub for Mac is trying to access this corrupted repository on reopen and I can't change it within the program before it crashes. I would rather not purge the system of files because I have other repositories saved in GitHub for Mac. </p>
  
  <p>How exactly would I be able to solve this issue or delete the reference to this local repository that is causing me massive issues? I have attempted to get an answer from the people at GitHub but they have not responded to me yet. Thank you. The error I am getting is below.</p>
  
  <pre><code>*** Terminating app due to uncaught exception 
  NSInternalInconsistencyException', reason: 'Received error from &lt;RACDynamicSignal: 0x600000e3dca0&gt; name:  in binding for key path` "headerContentViewModel" on &lt;GHChangesViewModel: 0x600000129420&gt;: 
  NSError { domain: GTGitErrorDomain, code: -12, description: "Failed to create reference to tracking branch from &lt;GTBranch: 0x600000e20c00&gt; name: refs/heads/master, shortName: master, sha:   
  b5db93cacaf51cde5ad27c605c4bdb114cd23605, remoteName: (null), repository: &lt;GTRepository: 0x60000041b4e0&gt; fileURL: file:///Users/name/Desktop/personalWebsite/", underlying error: NSError { domain: 
  GTGitErrorDomain, code: -12, description: "'https://github.com/name/git.git' is not a valid remote name." } }'
  terminating with uncaught exception of type NSExceptionabort() called
  </code></pre>