Checkin time data column, checkin module

Signed-off-by: Asai Neko <sugar@sne.moe>

data/user.go

@@ -1,6 +1,10 @@
 package data
 
-import "github.com/google/uuid"
+import (
+	"time"
+
+	"github.com/google/uuid"
+)
 
 type User struct {
 	Id       uint      `json:"id" gorm:"primarykey;autoincrement"`
@@ -11,7 +15,7 @@ type User struct {
 	Nickname string    `json:"nickname"`
 	Subtitle string    `json:"subtitle"`
 	Avatar   string    `json:"avatar"`
-	Checkin  bool      `json:"checkin" gorm:"not null;default:false"`
+	Checkin  time.Time `json:"checkin"`
 }
 
 func (self *User) GetByEmail(email string) error {
@@ -28,11 +32,11 @@ func (self *User) GetByUserId(userId string) error {
 	return nil
 }
 
-func (self *User) SetCheckinState(userId uuid.UUID, state bool) error {
+func (self *User) SetCheckinState(userId uuid.UUID, time time.Time) error {
 	if err := Database.Where("user_id = ?", userId).First(&self).Error; err != nil {
 		return err
 	}
-	self.Checkin = state
+	self.Checkin = time
 	Database.Save(&self)
 	return nil
 }