解決辦法：在setting.py的TEMPLATES‘DIRS'[]加入模版路徑

TEMPLATES = [
    {
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'DIRS': [os.path.join(BASE_DIR, 'templates')],
        #os.path.join(BASE_DIR, 'templates')沒了這句，
        # 會顯示django.template.exceptions.TemplateDoesNotExist: index.html
 

        'APP_DIRS': True,
        'OPTIONS': {
            'context_processors': [
                'django.template.context_processors.debug',
                'django.template.context_processors.request',
                'django.contrib.auth.context_processors.auth',
                'django.contrib.messages.context_processors.messages
 
',
            ],
        },
    },
]