Use CanCanCan for oauth clients controller

app/abilities/ability.rb

@@ -16,6 +16,7 @@ class Ability
 
     if user
       can :welcome, :site
+      can [:index, :new, :create, :show, :edit, :update, :destroy], ClientApplication
       can [:create, :edit, :comment, :subscribe, :unsubscribe], DiaryEntry
       can [:new, :create, :reply, :show, :inbox, :outbox, :mark, :destroy], Message
       can [:close, :reopen], Note

app/controllers/oauth_clients_controller.rb

@@ -3,7 +3,8 @@ class OauthClientsController < ApplicationController
 
   before_action :authorize_web
   before_action :set_locale
-  before_action :require_user
+
+  authorize_resource :class => ClientApplication
 
   def index
     @client_applications = current_user.client_applications