how to use cutom finders for authentication

[anuj9196]

Thank you dev for this plugin. It's really nice and easy to use.

But, since, this plugin has been abandoned and according to your doc, this can be achieved by custom finders in CakePHP, I'm having an issue with custom finders.

I used this plugin to allow login using either email or mobile number field along with password and there is no username field in the table.
But this is getting it hard to work. Can you please write a doc to use custom finders in CakePHP to allow login using multiple fields (even without username field)

stackoverflow reference : http://stackoverflow.com/questions/41928534/custom-finder-not-working-in-cakephp-3