add collation support.

config.json

@@ -1,7 +1,7 @@
 {
   "Host":"0.0.0.0",
   "Port":"8080",
-  "DSN": "sp:sp@tcp(192.168.1.70:3306)/syd_credit?parseTime=true&loc=Australia%2FSydney",
+  "DSN": "sp:sp@tcp(192.168.1.70:3306)/syd_credit?parseTime=true&loc=Australia%2FSydney&collation=utf8mb4_0900_ai_ci",
   "TlsCert": "/home/sp/go/src/fullchain.pem",
   "TlsKey": "/home/sp/go/src/privkey.pem",
   "Debug": true,