read after burn time

pkg/common/constant/constant.go

@@ -275,6 +275,7 @@ const (
 	FieldIsNotInGroup  = 6
 	FieldEx            = 7
 	FieldUnread        = 8
+	FieldBurnDuration  = 9
 )
 
 const (

pkg/common/db/model_struct.go

@@ -263,6 +263,7 @@ type Conversation struct {
 	DraftTextTime         int64  `gorm:"column:draft_text_time" json:"draftTextTime"`
 	IsPinned              bool   `gorm:"column:is_pinned" json:"isPinned"`
 	IsPrivateChat         bool   `gorm:"column:is_private_chat" json:"isPrivateChat"`
+	BurnDuration          int32  `gorm:"column:burn_duration;default:30" json:"burnDuration"`
 	GroupAtType           int32  `gorm:"column:group_at_type" json:"groupAtType"`
 	IsNotInGroup          bool   `gorm:"column:is_not_in_group" json:"isNotInGroup"`
 	UpdateUnreadCountTime int64  `gorm:"column:update_unread_count_time" json:"updateUnreadCountTime"`