>>>  python3 manage.py makemigrations
　　No changes detected


大多情况是未在setting页面注册应用

INSTALLED_APPS = [
'django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles',
'你的app名称',
]