using sha256 as hashing and salting with user's ID

[Wormhole]

I'm gonna use sha256 for my site,to secure my users passwords,and as salt i was thinking of usings the users id (int auto_increment). that will be unique but not very long and hard,and public(user.php?id=1) but it just matters if its unique right?\[code\]hash('sha256', $id . $password);\[/code\]