fix db session

app/plugins/__init__.py

@@ -183,13 +183,3 @@ class _PluginBase(metaclass=ABCMeta):
             channel=channel, mtype=mtype, title=title, text=text,
             image=image, link=link, userid=userid
         ))
-
-    def close(self):
-        """
-        关闭数据库连接
-        """
-        if self.db:
-            self.db.close()
-
-    def __del__(self):
-        self.close()