title: Django multiple databases error with routes
body: <p>I'm using 3 databases in my project:</p>
  
  <pre><code>DATABASES = {
      'default': {
          (postgres, read, write)...
      },
      'admission_db': {
          (postgres, read, write)...
      },
      'journals_db': {
          (mysql, read only)...
      }
  }
  DATABASE_ROUTERS = [
      'main.lib.DbRouter.DbRouter',
  ]
  </code></pre>
  
  <p>wrote db router:</p>
  
  <pre><code>class DbRouter:
  ...
  
      def allow_migrate(self, db, app_label, model=None, **hints):
          if db == 'admission_db':
              if model and model._meta.app_label == 'admission':
                  return True
              return app_label == 'admission'
          elif db == 'journals_db':
              return False
          return None
  </code></pre>
  
  <p>when i make migrate command</p>
  
  <pre><code>python manage.py migrate admission --database admission_db
  </code></pre>
  
  <p>it migrates normally, but when i try to make</p>
  
  <pre><code>python manage.py migrate,
  </code></pre>
  
  <p>it throws</p>
  
  <pre><code>django.db.utils.OperationalError: no such table: admission_educationform
  </code></pre>
  
  <p>because of it i can make make migrate on other apps.
  (python 3.5.2, django 1.10.5)
  what can be cause of problem?</p>