title: stacked bar chart from grouped object
body: <p>I get the expected count of following group-by query. But when I add <code>.plot.bar()</code> method, I get bar chart for each record.
  How do I get stacked bar chart?</p>
  
  <pre><code>df.groupby(['department', 'status'])['c_name'].count()
  
  department                                                status  
  Agriculture                                               Accepted      3
                                                            Pending       2
                                                            Rejected     13
  Department of Education and Training                  Accepted    290
                                                            Rejected     65
  Higher Education                                  Accepted    424
                                                            Pending      24
                                                            Rejected     92
  Medical Education and Research                    Accepted     34
                                                            Pending       3
                                                            Rejected      1
  </code></pre>
  
  <p>This will create a bar chart but not the stacked one.</p>
  
  <pre><code>.plot(kind='bar', stacked=True)
  </code></pre>
  
  <p>For each department there should be 3 colors (for Accepted, Pending and Rejected) </p>
  
  <hr>
  
  <p>Update:</p>
  
  <p>I managed using pivot.</p>
  
  <pre><code>gdf=df.groupby(['department', 'status'])['c_name'].count().reset_index()
  gdf.pivot(index='department', columns='status').plot(kind='bar', stacked=True)
  </code></pre>
  
  <p>But is it possible to improve the chart quality?</p>