add smtp_server

tool/config.json

@@ -23,6 +23,7 @@
     },
     "email": {
         "register_email": "register@magicpig.ntesmail.com",
-        "register_email_secret": "1UwDHapA7kzWgT9q"
+        "register_email_secret": "1UwDHapA7kzWgT9q",
+        "smtp_server": "smtphz.qiye.163.com"
     }
 }