public User AddUser(User user)
 {
     //check if exists, then add
     User existingUser = this.dbContext.Users.Where(u => u.FacebookId == user.FacebookId).FirstOrDefault();
     if (existingUser == null)
     {
         this.dbContext.Users.Add(user);
         this.dbContext.SaveChanges();
         return user;
     }
     return existingUser;
 }
 public User UpdateUser(User user)
 {
     dbContext.Entry(user).State = EntityState.Modified;
     this.dbContext.SaveChanges();
     return user;
 }