title: Make the current Git branch a master branch
body: <p>I have a repository in Git. I made a branch, then did some changes both to the master and to the branch.</p>
  
  <p>Then, tens of commits later, I realized the branch is in much better state than the master, so I want the branch to "become" the master and disregard the changes on master.</p>
  
  <p>I cannot merge it, because I don't want to keep the changes on master. What should I do?</p>
  
  <p><em>Extra</em>: In this case, the 'old' master has already been <code>push</code>-ed to another repository such as GitHub. How does this change things?</p>