Update wsMongoTicker.py

fix subscription

Author: s4w3d0ff

examples/ticker/wsMongoTicker.py

@@ -77,8 +77,8 @@ def on_open(self, ws):
                 {'$set': tick[market]},
                 upsert=True)
         print('Populated markets database with ticker data')
-        ws.send(json.dumps({'command': 'subscribe',
-                            'channel': 1002}))
+        self.ws.send(json.dumps({'command': 'subscribe',
+                                 'channel': 1002}))
 
     def start(self):
         self.t = Thread(target=self.ws.run_forever)