django orm创建数据表

Question

在model文件下已创建字段，setting都已设置。
from django.db import models
# Create your models here.
class UserTab(models.Model):
username = models.CharField(max_length=32)
password = models.CharField(max_length=32)
但执行出现一些错误：
D:\py\djangoItem>python manage.py makemigrations
Unknown command: 'makemigrations'
Type 'manage.py help' for usage.