feat: support custom SMTP port setting (#45)

* feat: support custom SMTP port setting

* fix: send SMTPPort value to frontend

---------

Co-authored-by: JustSong <quanpengsong@gmail.com>

common/constants.go

@@ -33,6 +33,7 @@ var MessagePersistenceEnabled = true
 var MessageRenderEnabled = true
 
 var SMTPServer = ""
+var SMTPPort = 587
 var SMTPAccount = ""
 var SMTPToken = ""
 

common/email.go

@@ -8,7 +8,7 @@ func SendEmail(subject string, receiver string, content string) error {
 	m.SetHeader("To", receiver)
 	m.SetHeader("Subject", subject)
 	m.SetBody("text/html", content)
-	d := gomail.NewDialer(SMTPServer, 587, SMTPAccount, SMTPToken)
+	d := gomail.NewDialer(SMTPServer, SMTPPort, SMTPAccount, SMTPToken)
 	err := d.DialAndSend(m)
 	return err
 }