Add: Method to add alternate text fro email

1. Add: Method to add alternate text fro email

notificationmdl/email/email.go

@@ -53,7 +53,7 @@ type Email struct {
 	subject     string
 	attachments []string
 	body        string
-	plainBody   string
+	plainBody   string // alternate text if template fails
 }
 
 func NewEmail(to, cc, bcc, attachments []string, from, subject, body string) *Email {
@@ -68,6 +68,11 @@ func NewEmail(to, cc, bcc, attachments []string, from, subject, body string) *Em
 	}
 }
 
+// SetAlternateText - set alternate text for email
+func (email *Email) SetAlternateText(plainBody string) {
+	email.plainBody = plainBody
+}
+
 // SendMail - send email service sends email as per the given html template and data
 //templateData can contain any type of values, including array, slice, map, struct and func
 func (email *Email) SendMail(templateFilePath string, templateData interface{}) error {