Add an example for the devise authenticator

[marcoow]

Devise-like middleware cab be implemented in middleware.js

[givanse]

I'm working on an example with ember-simple-auth-devise & ember-cli. (full rails server though) Do you think it would make sense to have it here? I can submit a PR if you tell me more about the file structure you want for the examples/docs.

[marcoow]

Would be great to link that once your finished! For the examples included in the repository though I think it's better when they're really simple and use just a fake server (don't want to actually include a full Rails project in the repo).

[givanse]

ember-cli + ember-simple-auth-devise: http://www.givan.se/p/00000000

[marcoow]

Thanks, added the link: eeb9c9f