Enable login via browserid/mozilla persona about hackathon-starter

[BPopson]

Persona is no longer actively developed by Mozilla. Mozilla has committed to operational and security support of the persona.org services until November 30th, 2016.

On November 30th, 2016, Mozilla will shut down the persona.org services. Persona.org and related domains will be taken offline.

If you run a website that relies on Persona, you need to implement an alternative login solution for your users before this date.

Source: https://developer.mozilla.org/en-US/Persona

[sahat]

After further investigation, I decided it is best not to include Persona into Hackathon Starter. Here is a summary:

• The email is already a unique field for LocalStrategy's login/signup. This new change requires to create another field, browserid, on the User model which it seems is just another email field. https://github.com/sahat/hackathon-starter/pull/64/files#diff-c6601fa9f2ae68b5ce23cfd416544f27R231.
• Requires custom javascript logic to handle login and logout: https://github.com/sahat/hackathon-starter/pull/64/files#diff-f485b1889bd3c96211c9236b0cf5daecR2
• Requires creating a new form with hidden input fields. When I first saw it, I thought it was added by mistake (a form with no submit button and only empty fields). https://github.com/sahat/hackathon-starter/pull/64/files#diff-4e0a14fee3faf718fe9c73cfd7e4787dR5
• Requires inclusion of a client-side library: https://github.com/sahat/hackathon-starter/pull/64/files#diff-5ed76714b00f35ca2d14be52cf7b1d08R12

Once again, I am all for simplicity of the project. Hackathon Starter is already complex enough that at this point I would rather welcome pull request that simplify and refactor existing code, instead of adding new features (unless they are self-contained).

Thank you either way @seafoodbuffet. I will mention this pull request in the README, for those who interested in adding Mozilla Persona to their projects.