title: Adding data frame below another data frame
body: <p>I want to do the following:</p>
  
  <p>I have a Actual Sales Dataframe</p>
  
  <pre><code>Dates       Actual
  24/04/2017  58
  25/04/2017  59
  26/04/2017  58
  27/04/2017  154
  28/04/2017  117
  29/04/2017  127
  30/04/2017  178
  </code></pre>
  
  <p>Another data frame of Predicted values</p>
  
  <pre><code>Dates           Predicted
  01/05/2017      68.54159
  02/05/2017      90.7313
  03/05/2017      82.76875
  04/05/2017      117.48913
  05/05/2017      110.3809
  06/05/2017      156.53363
  07/05/2017      198.14819
  </code></pre>
  
  <p>Add the predicted Sales data frame below the Actual data Frame in following manner:</p>
  
  <pre><code>Dates      Actual   Predicted
  24/04/2017  58  
  25/04/2017  59  
  26/04/2017  58  
  27/04/2017  154 
  28/04/2017  117 
  29/04/2017  127 
  30/04/2017  178 
  01/05/2017        68.54159
  02/05/2017        90.7313
  03/05/2017        82.76875
  04/05/2017        117.48913
  05/05/2017        110.3809
  06/05/2017        156.53363
  07/05/2017        198.14819
  </code></pre>