title: Add empty row with index in a Pandas dataframe
body: <p>In all the examples and answers on here that I've seen, if there is the need to add an empty row ina Pandas dataframe, all use: </p>
  
  <pre><code>ignore_index=True
  </code></pre>
  
  <p>What should I do if i want to leave the current index, and append an empty row to the dataframe with a given index?</p>