title: Django request.user.userprofile.save() not working
body: <p>I suppose to save user's avatar and contact. When I create a form of <code>userprofile</code> and update model with <code>request.user.userprofile.save()</code>, it turns out that nothing changed in database.</p>
  
  <p>I've tried many ways, including ModelForm, but I think it has nothing to do with the form, cuz when I directly using UserProfile.objects.filter(id=123).update(avatar=my_avatar) in view, no error raised but still nothing changed in database.</p>
  
  <p>It's very strange that when I debug it, slow the program down, it worked!
  Other models works just fine.</p>
  
  <pre><code>class UserProfile(models.Model):
  
      user = models.OneToOneField(User)
      avatar = models.CharField(max_length=100, blank=True, null=True)
      contact = models.CharField(max_length=64, blank=True, null=True)
  
  class PostUpdateUserProfileView(View):
  
      @method_decorator(mobile_login_required)
      def dispatch(self, request, *args, **kwargs):
          return super(PostUpdateUserProfileView, self).dispatch(request, *args, **kwargs)
  
      def post(self, request):
          request.user.userprofile.contact = 'test'
          request.user.userprofile.save(using='master')
  
  # DB SETTINGS
  DATABASES = {
      "default": {
          "ENGINE": "django.db.backends.mysql",
          "NAME": "db",
          "USER": "&lt;SAME_USR&gt;",
          "PASSWORD": "&lt;SAME_PWD&gt;",
          "HOST": "&lt;SAME_HOST&gt;",
          "PORT": "3306",
          "OPTIONS": {
              'init_command': "SET default_storage_engine=INNODB, sql_mode='STRICT_TRANS_TABLES'",
              'charset': 'utf8mb4',
          },
      },
      "master": {
          "ENGINE": "django.db.backends.mysql",
          "NAME": "db",
          "USER": "&lt;SAME_USR&gt;",
          "PASSWORD": "&lt;SAME_PWD&gt;",
          "HOST": "&lt;SAME_HOST&gt;",
          "PORT": "3306",
          'OPTIONS': {
              'init_command': "SET default_storage_engine=INNODB, sql_mode='STRICT_TRANS_TABLES'",
              'charset': 'utf8mb4',
          },
      }
  }
  </code></pre>
  
  <p>I thought this error might have sth to do with autocommit.</p>