title: djangae ImageField not working with CloudStorage
body: <p>i'm using Djangae to run my application on google appengine , i'm trying to store images to google CloudStorage ,</p>
  
  <p>i followed the same exact proceedure mentioned  <a href="https://github.com/potatolondon/djangae/blob/master/docs/storage.md" rel="nofollow noreferrer">here</a> but nothing written on the CloudStorage , no errors no exceptions !</p>
  
  <p>this is the model class that i have :</p>
  
  <pre><code>class Person(models.Model):
      user = models.ForeignKey(User, default=1)
      name = models.CharField(max_length=250,null=True)
      last_name = models.CharField(max_length=500)
      age= models.IntegerField(default=100)
      martial_status = models.CharField(max_length=20, choices=STATUS_CHOICES, default=("Single"))
      sex = models.CharField(max_length=20, choices=SEX_CHOICES, default=("Male"))
      mobile=models.CharField(max_length=26,default=0011)
      amount_paid=models.CharField(max_length=256,null=True)
      amount_left = models.CharField(max_length=256, null=True,blank=True)
      note=models.CharField(max_length=256,null=True,blank=True)
      address=models.CharField(max_length=256,null=True,blank=True)
      date = models.DateField(("Date"), default=date.today,blank=True)
      chief_complain = models.CharField(max_length=256,null=True,blank=True)
      treatment_plan=models.CharField(max_length=256,null=True,blank=True)
      treatment_done=models.CharField(max_length=256,null=True,blank=True)
      #picture = models.ImageField(blank=True)
      picture = models.ImageField(upload_to='/image/', storage=public_storage,blank=True)
      def __str__(self):
          return self.name
  </code></pre>
  
  <p>the ModelForm :</p>
  
  <pre><code>class PersonForm(forms.ModelForm):
  
      class Meta:
          model = Person
          fields = ['name', 'last_name', 'age', 'martial_status', 'mobile', 'sex',
                    'amount_paid','amount_left','note', 'address','date','picture','treatment_done','treatment_plan','chief_complain']
          widgets = {
              'name': forms.TextInput(attrs={'required': True, 'class': 'form-control',
                                               'placeholder': 'name'}),
              'last_name': forms.TextInput(attrs={'required': True, 'class': 'form-control',
                                             'placeholder': 'lastname'}),
              'age': forms.TextInput(attrs={'required': True, 'class': 'form-control',
                                             'placeholder': 'age'}),
              'amount_paid': forms.TextInput(attrs={'required': True, 'class': 'form-control',
                                             'placeholder': 'amount paid'}),
              'amount_left': forms.TextInput(attrs={'required': True, 'class': 'form-control',
                                             'placeholder': 'amount left'}),
              'note': forms.TextInput(attrs={'required': False, 'class': 'form-control',
                                             'placeholder': 'Patient History'}),
              'address': forms.TextInput(attrs={'required': False, 'class': 'form-control',
                                             'placeholder': 'Current address'}),
              'chief_complain': forms.TextInput(attrs={'required': False, 'class': 'form-control',
                                             'placeholder': 'chief complain'}),
              'treatment_plan': forms.Textarea(attrs={'required': False, 'class': 'form-control',
                                             'placeholder': 'treatment plan','rows':'3'}),
              'treatment_done': forms.Textarea(attrs={'required': False, 'class': 'form-control',
                                             'placeholder': 'treatment done','rows':'3'}),
  
  
  
  
          }
  </code></pre>
  
  <p>the template :</p>
  
  <pre><code>&lt;h2&gt;Add person&lt;/h2&gt;
    &lt;form method="post"&gt;
      {% csrf_token %}
  
  
  &lt;div class="row"&gt;
       &lt;div class="col-sm-4 form-group"&gt;
         &lt;label for="name" &gt;{% trans "Name" %}&lt;/label&gt;
         {{ form.name|add_class:"form-control" }}
        &lt;/div&gt;
  
  ..&lt;code snippet&gt;..
  
        &lt;div class="row"&gt;
         &lt;div class="col-sm-4 form-group"&gt;
         &lt;label for="address"&gt;{% trans "Address" %}&lt;/label&gt;
         {{ form.address|add_class:"form-control" }}
        &lt;/div&gt;
            &lt;div class="col-sm-4 form-group"&gt;
         &lt;label for="pic"&gt;{% trans "Picture" %}&lt;/label&gt;
          {{form.picture}}
        &lt;/div&gt;
        &lt;/div&gt;
  </code></pre>