This is the content of the models.py of my app. When i run syncdb or sql <appname> command, I'm getting error that Tags is not defined. Please help.
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from django.db import models

# Create your models here.

class Customer(models.Model):
	name = models.CharField(max_length = 50)

class Tweet(models.Model):
	content = models.CharField(max_length = 140)
	pub_date = models.DateTimeField()
	author = models.ForeignKey(Customer)
	tag_user = models.ForeignKey(Tags)
	tag_company = models.ForeignKey(Tags)

class Tags(models.Model):
	company_tags = models.CharField(max_length = 25)
	user_tag = models.CharField(max_length = 25)
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getting this error when i run the above file:
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aravind@aravindPC:~/djan-apps/twijango$ python manage.py sql tweetrack
Traceback (most recent call last):
  File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 443, in execute_from_command_line
    utility.execute()
  File "/usr/local/lib/python2.7/dist-packages/django/core/management/__init__.py", line 382, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 196, in run_from_argv
    self.execute(*args, **options.__dict__)
  File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 231, in execute
    self.validate()
  File "/usr/local/lib/python2.7/dist-packages/django/core/management/base.py", line 266, in validate
    num_errors = get_validation_errors(s, app)
  File "/usr/local/lib/python2.7/dist-packages/django/core/management/validation.py", line 30, in get_validation_errors
    for (app_name, error) in get_app_errors().items():
  File "/usr/local/lib/python2.7/dist-packages/django/db/models/loading.py", line 158, in get_app_errors
    self._populate()
  File "/usr/local/lib/python2.7/dist-packages/django/db/models/loading.py", line 64, in _populate
    self.load_app(app_name, True)
  File "/usr/local/lib/python2.7/dist-packages/django/db/models/loading.py", line 88, in load_app
    models = import_module('.models', app_name)
  File "/usr/local/lib/python2.7/dist-packages/django/utils/importlib.py", line 35, in import_module
    __import__(name)
  File "/home/aravind/djan-apps/twijango/tweetrack/models.py", line 8, in <module>
    class Tweet(models.Model):
  File "/home/aravind/djan-apps/twijango/tweetrack/models.py", line 12, in Tweet
    tag_user = models.ForeignKey(Tags)
NameError: name 'Tags' is not defined

    self.load_app(app_name, True)
  File "/usr/local/lib/python2.7/dist-packages/django/db/models/loading.py", line 88, in load_app
    models = import_module('.models', app_name)
  File "/usr/local/lib/python2.7/dist-packages/django/utils/importlib.py", line 35, in import_module
    __import__(name)
  File "/home/aravind/djan-apps/twijango/tweetrack/models.py", line 8, in <module>
    class Tweet(models.Model):
  File "/home/aravind/djan-apps/twijango/tweetrack/models.py", line 12, in Tweet
    tag_user = models.ForeignKey(Tags)
NameError: name 'Tags' is not defined