INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'django.contrib.sites',
    'allauth',
    'allauth.account',
    'allauth.socialaccount',
      # 下面是第三方账号相关的，比如我选了weibo和github
    'allauth.socialaccount.providers.weibo',
     'allauth.socialaccount.providers.github',
]
 # django-allauth相关设置
AUTHENTICATION_BACKENDS = (
      # django admin所使用的用户登录与django-allauth无关
      'django.contrib.auth.backends.ModelBackend',
      # `allauth` specific authentication methods, such as login by e-mail
      'allauth.account.auth_backends.AuthenticationBackend',
)
# 前面我们app里添加了django.contrib.sites,需要设置
SITE_ID = 1
LOGIN_REDIRECT_URL = '/'
ACCOUNT_AUTHENTICATION_METHOD = 'username_email'
ACCOUNT_EMAIL_REQUIRED = True

# ACCOUNT_AUTHENTICATION_METHOD = 'username_email'的作用是当用户登录时，既可以使用用户名也可以使用email， 其他可选的值是 "username"、"email" ，ACCOUNT_EMAIL_REQUIRED = True要求用户注册时必须填写email，默认False，email是选填的。