Add Facebook authentication support

[rushidesai]

A very basic implementation. Also uses Facebook profile picture instead of gravatar.

[claudioc]

Hi @rushidesai and thanks for the PR!

I'm not sure I want to merge it, though... I'd like to maintain the "core" as simple as possible (and you know that those authentication models can break, in the future), using - for now - only the Google login as the "external" one.

Maybe in a future interaction I'll try to separate the authentication methods in more de-coupled way (as "components").

Thank you again

[Morgul]

Now that google has deprecated the OpenID login, maybe it's worth reconsidering merging this in?

[claudioc]

@Morgul I have just updated the authentication of Jingo to be able to use the OAuth 2 system (and removed the OpenID 2 altogether).

I am still not closing this PR though... still thinking about it :)

[almereyda]

@rushidesai @claudioc @Morgul I think we can move forward creating jingo-* plugins on npm. I am also interested in having other authentication systems and am now working on a PR to include Persona within the 24 Pull Requests initiative. I think it doesn't even count as evel as Google and is a proper solution if you only want to have email validation.

[chevcast]

+1

My wife and I own mini pigs and bought the domain Pigipedia.com because there is a distinct lack of factual information on the web about raising mini pigs as house pets. The most helpful info we've gotten is from a smattering of random files members of a Facebook group have uploaded. This Facebook group seems to be the current most popular destination for mini pig owners.

I love the simplicity of this wiki so we're going to use it, but to make it easy for Facebook group members to come contribute and help out I'll have to maintain a fork with this PR rolled in so they can use Facebook to authenticate.

Not a huge deal, but if this wiki just had some more authentication options someone like me would have zero reason to fork it :)