title: Unable to plot dataframe using seaborn barplot
body: <p>I have been able to use pandas <code>groupby</code> to create a new <code>DataFrame</code> but I'm getting an error when I create a <code>barplot</code>.
  The groupby command:</p>
  
  <p><code>invYr = invoices.groupby(['FinYear']).sum()[['Amount']]</code></p>
  
  <p>Which creates a new <code>DataFrame</code> that looks correct to me.</p>
  
  <p><a href="http://i.stack.imgur.com/9hhOX.png" rel="noreferrer">New <code>DataFrame</code> invYr</a></p>
  
  <p>Running:</p>
  
  <p><code>sns.barplot(x='FinYear', y='Amount', data=invYr)</code></p>
  
  <p>I get the error: </p>
  
  <p><code>ValueError: Could not interperet input 'FinYear'</code></p>
  
  <p>It appears that the issue is related to the index, being FinYear but unfortunately I have not been able to solve the issue even when using <code>reindex</code>.</p>