public void Participate(string userId, int courseId)
{
CourseUsers courseUsers = repository.CourseUsers
.FirstOrDefault(c => c.AppUserId == userId && c.CourseId == courseId);
if (courseUsers == null)
{
//add user to course
repository.AddUserToCourse(userId, courseId);
//notification
_ = ShowNewUserNotification(userId, courseId);
_ = HideParticipateBtn(userId, courseId);
}
}
