更新文档，完善插件功能

applications/extensions/__init__.py

@@ -7,9 +7,15 @@ from .init_mail import init_mail, mail as flask_mail
 from .init_upload import init_upload
 from .init_migrate import init_migrate
 from .init_session import init_session
+from .init_plugins import register_plugin, broadcast_execute
 
 
 def init_plugs(app: Flask) -> None:
+    # 注册插件
+    register_plugin(app)
+    broadcast_execute(app, 'event_begin')
+
+    # 注册 Flask 功能
     init_login_manager(app)
     init_databases(app)
     init_template_directives(app)
@@ -17,4 +23,4 @@ def init_plugs(app: Flask) -> None:
     init_mail(app)
     init_upload(app)
     init_migrate(app)
-    init_session(app)
+    init_session(app)