Various fixes (#5)

* Fixes #1

* Fixes #2

* Fixes #3

* Fixes #4

models/session.go

@@ -1,9 +1,17 @@
 package models
 
-import "gorm.io/gorm"
+import (
+	"gorm.io/gorm"
+	"time"
+)
 
 type Session struct {
 	gorm.Model
 	Identifier string
 	UserID     uint
+	ExpiresAt  time.Time
+}
+
+func (s Session) HasExpired() bool {
+	return s.ExpiresAt.Before(time.Now())
 }