title: Repeat row number of times based on column value
body: <p>I have table which looks like this:</p>
  
  <pre><code>| name |  start_date   |  duration_day|
  ========================================
  |   A  |  2015-01-01   |       3      |
  |   B  |  2015-01-02   |       2      |
  </code></pre>
  
  <p>And now I want to get an output like so:</p>
  
  <pre><code>   | name |     date   |
     =====================
     |  A   | 2015-01-01 |
     |  A   | 2015-01-02 |
     |  A   | 2015-01-03 |
     |  B   | 2015-01-02 |
     |  B   | 2015-01-03 |
  </code></pre>
  
  <p>How can I do this in PostgreSQL?</p>