Add OIDC capability

app/controllers/oidc_controller.rb

@@ -1,6 +1,6 @@
 class OidcController < ApplicationController
   # Discovery and JWKS endpoints are public
-  allow_unauthenticated_access only: [:discovery, :jwks, :token]
+  allow_unauthenticated_access only: [:discovery, :jwks, :token, :userinfo]
   skip_before_action :verify_authenticity_token, only: [:token]
 
   # GET /.well-known/openid-configuration

app/models/oidc_authorization_code.rb

@@ -15,7 +15,7 @@ class OidcAuthorizationCode < ApplicationRecord
     expires_at <= Time.current
   end
 
-  def valid?
+  def usable?
     !used? && !expired?
   end