perf(assets): 优化节点树

修改树策略，做读优化，写的速度降低

apps/perms/migrations/0014_build_users_perm_tree.py

@@ -0,0 +1,27 @@
+# Generated by Django 2.2.13 on 2020-08-21 08:20
+
+from django.db import migrations
+from perms.tasks import dispatch_mapping_node_tasks
+
+
+def start_build_users_perm_tree_task(apps, schema_editor):
+    User = apps.get_model('users', 'User')
+    RebuildUserTreeTask = apps.get_model('perms', 'RebuildUserTreeTask')
+
+    user_ids = User.objects.all().values_list('id', flat=True).distinct()
+    RebuildUserTreeTask.objects.bulk_create(
+        [RebuildUserTreeTask(user_id=i) for i in user_ids]
+    )
+
+    dispatch_mapping_node_tasks.delay()
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('perms', '0013_rebuildusertreetask_usergrantedmappingnode'),
+    ]
+
+    operations = [
+        migrations.RunPython(start_build_users_perm_tree_task)
+    ]