change receiver field type

mail/mail.go

@@ -9,19 +9,10 @@ import (
 
 type Email struct {
 	Path      string
-	Sender    string   `json:"sender"`
-	Receivers []string `json:"receivers"`
-	Subject   string   `json:"subject"`
-	Content   string   `json:"content"`
-}
-
-func NewEmail(sender string, receivers []string, subject, content string) Email {
-	return Email{
-		Sender:    sender,
-		Receivers: receivers,
-		Subject:   subject,
-		Content:   content,
-	}
+	Sender    string `json:"sender"`
+	Receivers string `json:"receivers"`
+	Subject   string `json:"subject"`
+	Content   string `json:"content"`
 }
 
 func FromJSON(path string) (Email, error) {
@@ -39,10 +30,14 @@ func FromJSON(path string) (Email, error) {
 	return mail, nil
 }
 
+func (e Email) GetReceivers() []string {
+	return strings.Split(e.Receivers, ",")
+}
+
 func (e Email) Generate() []byte {
 	mail := fmt.Sprintf(
 		"To: %s\nFrom: %s\nContent-Type: text/html;charset=utf-8\nSubject: %s\n\n%s",
-		strings.Join(e.Receivers, ","),
+		e.Receivers,
 		e.Sender,
 		e.Subject,
 		e.Content,