Consider implementing login and logout functionality

[artur-intech]

After having read project description - in particular the part "This simple gem will help you enable login/logout through [GitHub OAuth]" - I am kind of puzzled to understand whether this gem should handle all that stuff with cookies explained in the readme.

Currently there is too much hassle to start using the gem, in my opinion.

Basically if the gem is really about login and logout, then I would rather incorporate the following (at least) right into it:

get '/github-callback' do
  cookies[:glogin] = GLogin::Cookie::Open.new(
    settings.glogin.user(params[:code]),
    # The same encryption secret that we were using above:
    secret
  ).to_s
  redirect to('/')
end


get '/logout' do
  cookies.delete(:glogin)
  redirect to('/')
end

On the other hand, if it only concerns login with Github, then I wonder whether we need to deal with logging out at all, since it has nothing to do with Github.