title: Transform data in spark scala column to row
body: <p>Input Dataset: </p>
  
  <pre><code>CustomerID CustomerName Sun Mon Tue
     1          ABC        0   12  10
     2          DEF        10   0   0
  </code></pre>
  
  <p>Required Output Dataset:</p>
  
  <pre><code>CustomerID CustomerName Day  Value
      1         ABC       Sun   0
      1         ABC       Mon   12
      1         ABC       Tue   10
      2         DEF       Sun   10
      2         DEF       Mon   0
      2         DEF       Tue   0
  </code></pre>
  
  <p>Please note, that the number of "Sun Mon Tue" columns are 82 in my dataset!</p>