feat: 支持自定义认证 backend；统一其他认证方式的信号触发逻辑；

apps/users/migrations/0040_alter_user_source.py

@@ -0,0 +1,18 @@
+# Generated by Django 3.2.13 on 2022-08-24 02:57
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('users', '0039_auto_20211229_1852'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='user',
+            name='source',
+            field=models.CharField(choices=[('local', 'Local'), ('ldap', 'LDAP/AD'), ('openid', 'OpenID'), ('radius', 'Radius'), ('cas', 'CAS'), ('saml2', 'SAML2'), ('oauth2', 'OAuth2'), ('custom', 'Custom')], default='local', max_length=30, verbose_name='Source'),
+        ),
+    ]