public bool Save(UserRelation _UserRelation)
 {
     db.UsersRelations.Add(_UserRelation);
     db.SaveChanges();
     return true;
 }
 public void Update(UserRelation _UserRelation)
 {
     db.SaveChanges();
 }
 public void Delete(UserRelation _cours)
 {
     db.UsersRelations.Remove(_cours);
     db.SaveChanges();
 }