title: Add multiple option values for git config option
body: <p>I can add manually the following to the git config:</p>
  
  <pre><code>[branch "master"]
      remote = origin
      mergeOptions = --edit --no-ff
  </code></pre>
  
  <p>However, when I try to add the same using command line like this:</p>
  
  <pre><code>$ git config branch.master.mergeOptions --edit --no-ff
  </code></pre>
  
  <p>Only the first <code>--edit</code> values are added to the config. How to add both <code>--edit</code> and <code>--no-ff</code>?</p>