我的Django项目结构是：

/proj
  /frontend
  /server
    /proj
    /app1
    /app2
  manage.py

如何运行python manage.py startapp app_name，以便我新创建的应用程序位于/server目录中？我尝试在server目录中运行django-admin.py startapp appname来创建应用程序，但最终会出现此错误：

$ ./manage.py runserver
Traceback (most recent call last):
  File "./manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/Users/bli1/Development/Django/CL/cherngloong/cherngloong/lib/python2.7/site-packages/django/core/management/__init__.py", line 351, in execute_from_command_line
    utility.execute()
  File "/Users/bli1/Development/Django/CL/cherngloong/cherngloong/lib/python2.7/site-packages/django/core/management/__init__.py", line 343, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/Users/bli1/Development/Django/CL/cherngloong/cherngloong/lib/python2.7/site-packages/django/core/management/__init__.py", line 177, in fetch_command
    commands = get_commands()
  File "/Users/bli1/Development/Django/CL/cherngloong/cherngloong/lib/python2.7/site-packages/django/utils/lru_cache.py", line 101, in wrapper
    result = user_function(*args, **kwds)
  File "/Users/bli1/Development/Django/CL/cherngloong/cherngloong/lib/python2.7/site-packages/django/core/management/__init__.py", line 72, in get_commands
    for app_config in reversed(list(apps.get_app_configs())):
  File "/Users/bli1/Development/Django/CL/cherngloong/cherngloong/lib/python2.7/site-packages/django/apps/registry.py", line 137, in get_app_configs
    self.check_apps_ready()
  File "/Users/bli1/Development/Django/CL/cherngloong/cherngloong/lib/python2.7/site-packages/django/apps/registry.py", line 124, in check_apps_ready
    raise AppRegistryNotReady("Apps aren't loaded yet.")
django.core.exceptions.AppRegistryNotReady: Apps aren't loaded yet.