title: django database router cannot import name connection
body: <p>i have issue with the DB Router on Django 1.4 (python 2.6). I have follow the documentation (https://docs.djangoproject.com/en/dev/topics/db/multi-db/#automatic-database-routing) but when i run my server i have this following error message:</p>
  
  <pre><code>django.core.exceptions.ImproperlyConfigured: Error importing database router MyDBRouter: "cannot import name connection"
  </code></pre>
  
  <p>My settings.py</p>
  
  <pre><code>DATABASES = {
      'default': {
          ...
      },
      'other' : {
          ...
      }
  }
  DATABASE_ROUTERS = ['core.models.MyDBRouter',]
  </code></pre>
  
  <p>here the db router code :</p>
  
  <pre><code>class MyAppRouter(object):
      def db_for_read(self, model, **hints):
          "Point all operations on myapp models to 'other'"
          if model._meta.app_label == 'myapp':
              return 'other'
          return None
  
      def db_for_write(self, model, **hints):
          "Point all operations on myapp models to 'other'"
          if model._meta.app_label == 'myapp':
              return 'other'
          return None
  
      def allow_relation(self, obj1, obj2, **hints):
          "Allow any relation if a model in myapp is involved"
          if obj1._meta.app_label == 'myapp' or obj2._meta.app_label == 'myapp':
              return True
          return None
  
      def allow_syncdb(self, db, model):
          "Make sure the myapp app only appears on the 'other' db"
          if db == 'other':
              return model._meta.app_label == 'myapp'
          elif model._meta.app_label == 'myapp':
              return False
          return None
  </code></pre>
  
  <p>I have try to replace None by 'default' but it still doesn't work.</p>