title: Django/Chartit NameError: global name 'MonthlyWeatherByCity' is not defined
body: <p>I am trying to product plots in my Django site using Chartit. I am following the official tutorial, but getting the following error as I try to navigate to my page. </p>
  
  <pre><code>NameError at /chart/ &lt;br&gt;
  global name 'MonthlyWeatherByCity' is not defined
  </code></pre>
  
  <p>I would appreciate any tips that might solve this issue. I am using the demo database from Chartit, I have run <code>python manage.py syncdb</code> before I started the server. </p>
  
  <p>models.py looks like: </p>
  
  <pre><code>from django.db import models
  
  class MonthlyWeatherByCity(models.Model):
      month = models.IntegerField()
      boston_temp = models.DecimalField(max_digits=5, decimal_places=1)
      houston_temp = models.DecimalField(max_digits=5, decimal_places=1)
  </code></pre>
  
  <p>view.py looks like: </p>
  
  <pre><code>from chartit import DataPool,Chart
  from django.template import RequestContext
  from django.template import Context,loader
  from django.shortcuts import render_to_response
  from django.http import HttpResponse
  
  def weather_chart_view(request):
      #Step 1: Create a DataPool with the data we want to retrieve.
      weatherdata = \
          DataPool(
             series=
              [{'options': {
                 'source': MonthlyWeatherByCity.objects.all()},
                'terms': [
                  'month',
                  'houston_temp',
                  'boston_temp']}
               ])
  
      #Step 2: Create the Chart object
      cht = Chart(
              datasource = weatherdata,
              series_options =
                [{'options':{
                    'type': 'line',
                    'stacking': False},
                  'terms':{
                    'month': [
                      'boston_temp',
                      'houston_temp']
                    }}],
              chart_options =
                {'title': {
                     'text': 'Weather Data of Boston and Houston'},
                 'xAxis': {
                      'title': {
                         'text': 'Month number'}}})
  
      #Step 3: Send the chart object to the template.
      return render_to_response({'weatherchart': cht})
  </code></pre>
  
  <p>chart.html in template looks like: </p>
  
  <pre><code>&lt;!DOCTYPE html&gt;
  &lt;html&gt;
    &lt;head&gt;
      &lt;script type="text/javascript" src="/static/js/jquery.min.js"&gt;&lt;/script&gt;
      &lt;script type="text/javascript" src="/static/js/highcharts.js"&gt;&lt;/script&gt;
      {% load chartit %}
      {{ weatherchart|load_charts:"container" }}
  
    &lt;/head&gt;
    &lt;body&gt;
      &lt;div id="container" style="width:100%; height:400px;"&gt;&lt;/div&gt;
    &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>