Passportist
Add it to your Gemfile
gem 'passportist', github: 'evrone/passportist'
You should have those attributes in your User model: uid, token, email, name, and nickname. After that, add this line to your user.rb file:
attr_accessible :uid, :token, :email, :name, :nickname, as: :passportist
Please, use this as: :passportist for better security.
Add this to your config/routes file:
mount Passportist::Engine, at: '/passportist'
Then create an initializer in config/initializers/passportist.rb:
Passportist.access_token = 'YOUR VERY SECRET ACCESS TOKEN'
And that's it! You should create a new application at http://passport.evrone.ru now.
For authentication through Passport use something like this:
= link_to 'Sign in', 'http://passport.evrone.ru/authenticate'
You can use button_to, too: we can get both GET and POST for this route.