/**
  * Send email to participants to complete there registration
  */
 public function sendParticipantCompleteRegistrationMailCommand()
 {
     $participants = $this->participantRepository->findUncompletedParticipants();
     /** @var Participant $participant */
     foreach ($participants as $participant) {
         $this->mailService->sendParticipantCompleteRegistrationMail($participant);
         $participant->setLastEmailSent(new \DateTime());
         $this->participantRepository->update($participant);
     }
 }