orm fix create index

@@ -178,7 +178,7 @@ func getDbCreateSql(al *alias) (sqls []string, tableIndexes map[string][]string)
 		}
 
 		for _, names := range sqlIndexes {
-			name := strings.Join(names, "_")
+			name := mi.table + "_" + strings.Join(names, "_")
 			cols := strings.Join(names, sep)
 			sql := fmt.Sprintf("CREATE INDEX %s%s%s ON %s%s%s (%s%s%s);", Q, name, Q, Q, mi.table, Q, Q, cols, Q)
 			tableIndexes[mi.table] = append(tableIndexes[mi.table], sql)

@@ -81,6 +81,7 @@ type User struct {
 func (u *User) TableIndex() [][]string {
 	return [][]string{
 		[]string{"Id", "UserName"},
+		[]string{"Id", "Created"},
 	}
 }
 
@@ -121,6 +122,12 @@ type Post struct {
 	Tags    []*Tag    `orm:"rel(m2m)"`
 }
 
+func (u *Post) TableIndex() [][]string {
+	return [][]string{
+		[]string{"Id", "Created"},
+	}
+}
+
 func NewPost() *Post {
 	obj := new(Post)
 	return obj