No changes detected or App 'blog' could not be found. Is it in INSTALLED_APPS?

出现该问题的原因：

　　django没有在setting.py的配置文件中找到app内容，需要增加app的名称

 E:\PycharmProjects\Mysite>python manage.py makemigrations
 No changes detected

 E:\PycharmProjects\Mysite>python manage.py makemigrations blog
 App 'blog' could not be found. Is it in INSTALLED_APPS?

　　setting.py 中并未有blog项目的名称

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

　　增加后的即可解决上述问题

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'blog'
]

===============可运行命令成功=====================

E:\PycharmProjects\Mysite>python manage.py makemigrations
Migrations for 'blog':
  blog\migrations\0001_initial.py
    - Create model UserInfo