title: How to draw grid lines behind matplotlib bar graph
body: <pre><code>x = ['01-02', '02-02', '03-02', '04-02', '05-02']
  y = [2, 2, 3, 7, 2]
  
  fig, ax = plt.subplots(1, 1)
  ax.bar(range(len(y)), y, width=0.3,align='center',color='skyblue')
  plt.xticks(range(len(y)), x, size='small')
  plt.savefig('/home/user/graphimages/foo2.png')
  plt.close()
  </code></pre>
  
  <p>I want to draw grid lines (of x &amp; y) behind the bar graph.</p>