func SendEmailViaGmail(c *Config, subject string, htmlContent string) string {
	d := gomail.NewDialer("<http://smtp.gmail.com|smtp.gmail.com>", 587, c.GmailAccount, c.GmailAppPassword)
	d.TLSConfig = &tls.Config{InsecureSkipVerify: true}

	// Send emails using d.
	m := gomail.NewMessage()
	m.SetAddressHeader("From", c.From, "Pinot Slack Email Digest")
	m.SetHeader("To", <http://c.To|c.To>)
	m.SetHeader("Subject", subject)
	m.SetBody("text/html", htmlContent)

	err := d.DialAndSend(m)
	if err != nil {
		fmt.Println("Failed to send the mail via Sendgrid:  " + err.Error())
		return "Failed to send mail via Sendgrid: " + err.Error()
	} else {
		msg := fmt.Sprintf("Daily digest successfully sent with the title: `%s`\n", DigestTitle())
		fmt.Println(msg)
		return msg
	}
}