def send_reject_message(professor, course)
    RestClient.post "https://api:key-6f2ddc1440a8cb30defa080219767e6e@api.mailgun.net/v3/sandboxd878e942441a4dfe8de8574efe8459b0.mailgun.org",
                    :from => "ETS Admin <postmaster@sandboxd878e942441a4dfe8de8574efe8459b0.mailgun.org>",
                    :to => professor.email,
                    :subject => "Your Webcast Request has Been Denied",