title: Migrating legacy passwords to CakePHP 3
body: <p>I'm reading the Auth documentation on Cake 3's website <a href="http://book.cakephp.org/3.0/en/controllers/components/authentication.html">here</a>, and I'm still slightly confused on how to migrate my users' passwords to my new application.</p>
  
  <p>It says to include the FallbackPasswordHasher class, but if that's the case, where do I place the salt for the legacy password (as it's different for the new site)? Other than that, everything seems fairly self-explanatory. </p>
  
  <p>I have a few different but related sites that I'm consolidating into one website that will provide the same services across multiple businesses, so I need to import users' passwords from a variety of sites with different salts.</p>