增加跨域配置，以及增加配置说明

example/main.go

@@ -2,10 +2,9 @@ package main
 
 import (
 	"code.hoteas.com/hoteas/hotime"
-	"code.hoteas.com/hoteas/hotime/dri/mysql"
+	"code.hoteas.com/hoteas/hotime/tools/db"
 	"fmt"
 	"strings"
-
 	//"go.hoteas.com/hotime/cache"
 	"golang.org/x/net/websocket"
 	"time"
@@ -32,8 +31,10 @@ func main() {
 	//ca.Cache("xyzo","dasdas")
 	//ca.Cache("xyz*",nil)
 	//fmt.Println(ca.Cache("xyzm").Data)
-
-	mysql.SetDB(&appIns)
+	//mysql
+	//mysql.SetDB(&appIns)
+	//自动选择数据库
+	db.SetDB(&appIns)
 
 	//appIns.SetConnectDB(func(err ...*hotime.Error) *sql.DB {
 	//	query := appIns.Config.GetString("dbUser") + ":" + appIns.Config.GetString("dbPwd") +