As of end of Nov 2016, the Mozilla Persona service is being taken down. I am trying to set up our lagotto instance to use username/password method (/users/sign_in). Has anybody got a procedure for this?
I found it by trial and error. You login in using Persona and then go to the "Your Account" dashboard. Then edit your account details with the pencil icon top right. Add a password and it will be put in the mysql database and can be used to log in. Apologies if this is obvious to seasoned users but it took a while to find.