add system user perm api (#4108)

apps/perms/serializers/system_user_permission.py

@@ -0,0 +1,18 @@
+from rest_framework import serializers
+from ..hands import SystemUser
+
+__all__ = [
+    'SystemUserSerializer',
+]
+
+
+class SystemUserSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = SystemUser
+        fields = [
+            'id', 'name', 'username', 'protocol',
+            'login_mode', 'login_mode_display',
+            'priority', 'username_same_with_user',
+            'auto_push', 'cmd_filters', 'sudo', 'shell', 'comment',
+            'sftp_root', 'date_created', 'created_by'
+        ]