fix db session

app/plugins/__init__.py

@@ -184,3 +184,10 @@ 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()