title: Django populating form field from another app model
body: <p>i have two apps first is inputs and second is boq
  inputs contains a model building
  boq contains a model boq model
  My inputs model looks like</p>
  
  <pre><code>class building(models.Model):
  
      building = models.CharField(max_length=300)
  </code></pre>
  
  <p>My boq model looks like</p>
  
  <pre><code>class boqmodel(models.Model):
      code = models.IntegerField()
      building =models.CharField(max_length=300)
      level = models.CharField(max_length=300)
      activity = models.CharField(max_length=300)
      subactivity = models.CharField(max_length=300)
      duration=models.IntegerField()
      linkactivity= models.CharField(max_length=300)
      linktype= models.CharField(max_length=300)
      linkduration=models.IntegerField()
      plannedstart=models.DateField()
      plannedfinish=models.DateField()
      actualstart=models.DateField()
      actualfinish=models.DateField()
  </code></pre>
  
  <p>i have aform in boq </p>
  
  <pre><code>class boqform(forms.ModelForm):
      class Meta:
          model = boqmodel
          fields=['code',
              'building',
              'level',
              'activity',
              'subactivity',
              'duration',
              'linkactivity',
              'linktype',
              'linkduration',
              'plannedstart',
              'plannedfinish',
              'actualstart',
              'actualfinish']
  </code></pre>
  
  <p>Now in my boqform for field building i need the form to have a dropdown from values in building model</p>