增加用户登录

包括用户model、用户登录模板、登录api和测试。

account/models.py

@@ -7,9 +7,21 @@ class AdminGroup(models.Model):
     pass
 
 
+class UserManager(models.Manager):
+    use_in_migrations = True
+
+    def get_by_natural_key(self, username):
+        return self.get(**{self.model.USERNAME_FIELD: username})
+
+
 class User(AbstractBaseUser):
     username = models.CharField(max_length=30, unique=True)
     admin_group = models.ForeignKey(AdminGroup, null=True, on_delete=models.SET_NULL)
 
+    USERNAME_FIELD = 'username'
+    REQUIRED_FIELDS = []
+
+    objects = UserManager()
+
     class Meta:
         db_table = "user"