title: Can not discard all changes Xcode
body: <p>2 and we are working on a shared Github Project. </p>
  
  <p>Sadly I uploaded the UserInterfaceState.xcuserstate file to Github. 
  My Partner just uploaded a version of our App witch works fine but makes it impossible for me to make changes. When I try to commit and push it failed because "The local repository is out of date" which makes sense. So I discard all changes and try to pull. But pulling failes because I make changes in UserInterfaceState.xcuserstate right after I discard changes. </p>
  
  <p>So basically I need to remove UserInterfaceState.xcuserstate from my Github upload. </p>
  
  <p>I tried to delete the file on Github webend wich worked but doesn't solved the problem. 
  Then I tried to do something with the .gitignore file. I generated one by using touch .gitignore but I sadly don't find the file and even when I don't know exactly what to do with it. </p>