title: Want to Convert a Website password Encryption from SHA1 to SHA256
body: <p>just looking for some advise.
  I have a website with around 2500 users - small but growing.
  I built it with using SHA1 encryption on the passwords.
  I've since read the SHA1 is insecure and would like to change to say SHA256 with a Salt.</p>
  
  <p>Does anyone have any advice on how to make a transition like this?
  Would be great if I could decrypt the passwords and just re-hash them but it doesn't appear doing able.</p>
  
  <p>thx
  Adam</p>