title: Change branch parent
body: <p>Have following branches structure:</p>
  
  <pre><code>                       master
                       /       \
                  BranchA      BranchB
  </code></pre>
  
  <p>But it should be:</p>
  
  <pre><code>                 master
                    /           
              BranchA        
                 /
           BranchB
  </code></pre>
  
  <p>Could anyone advice how to re-hang BranchB as child of BranchA?</p>