feat: channel email is done

channel/email.go

@@ -0,0 +1,18 @@
+package channel
+
+import (
+	"errors"
+	"message-pusher/common"
+	"message-pusher/model"
+)
+
+func SendEmailMessage(message *Message, user *model.User) error {
+	if user.Email == "" {
+		return errors.New("未配置邮箱地址")
+	}
+	subject := message.Description
+	if subject == "" {
+		subject = message.Title
+	}
+	return common.SendEmail(subject, user.Email, message.Content)
+}