Update the credentials associated with application user.

  Args:
    client_id: str Client Id retrieved from the developer's console.
    client_secret: str Client Secret retrieved from the developer's console.
    refresh_token: str Refresh token generated with the above client id/secret.
    adwords_manager_cid: str Customer Id for the AdWords manager account.
    developer_token: str Developer Token for the AdWords account.

def UpdateUserCredentials(client_id, client_secret, refresh_token,
                          adwords_manager_cid, developer_token):
  """Update the credentials associated with application user.

  Args:
    client_id: str Client Id retrieved from the developer's console.
    client_secret: str Client Secret retrieved from the developer's console.
    refresh_token: str Refresh token generated with the above client id/secret.
    adwords_manager_cid: str Customer Id for the AdWords manager account.
    developer_token: str Developer Token for the AdWords account.
  """
  app_user = AppUser.query(AppUser.user == users.get_current_user()).fetch()[0]

  app_user.client_id = client_id
  app_user.client_secret = client_secret
  app_user.refresh_token = refresh_token
  app_user.adwords_manager_cid = adwords_manager_cid
  app_user.developer_token = developer_token

  app_user.put()