public void CreateInvitation(User invitedUser)
{
var client = new EmailClient(sender: EmailCredentials.Email,
senderPassword: EmailCredentials.Password,
host: ConfigurationManager.AppSettings["appSettings:emailHost"]);
var registrationTokenUrlEnc = WebUtility.UrlEncode(invitedUser.RegistrationToken);
var baseUrl = ConfigurationManager.AppSettings["appSettings:websiteUrl"];
var invitationUrl = baseUrl + Strings.UserInvitationUrlPath + "?registrationToken=" + registrationTokenUrlEnc;
var emailBody = string.Format(format: _htmlString, invitedUser.FirstName, invitationUrl);
var subject = Strings.UserInvitationSubject;
client.SendEmailInBackground(subject, emailBody, invitedUser.Email);
}