title: find by all by an Id, but exclude certain Ids
body: <p><strong>I am going over Public Activity Gem Railscast Vid. (<a href="http://railscasts.com/episodes/406-public-activity" rel="nofollow">http://railscasts.com/episodes/406-public-activity</a>)</strong> </p>
  
  <p>Everything works fine, but I would like to be able to find all given activities performed except those that contain a recipient_id that belongs to Current_User</p>
  
  <p>I have a method working(activities) which allows me to find all activities performed by all users</p>
  
  <p>And this second method(notifications) to find all activities where recipient_id equals Current_User</p>
  
  <p><strong>CONTROLLER</strong></p>
  
  <pre><code>**(finds all activities)**
  def activities
    @title = "Activities"
    @activities = PublicActivity::Activity.order("created_at desc").where(owner_id: current_user.followed_users.all, owner_type: "User") 
    @user = User.find_by_username(params[:id])
    render 'activities'
  end
  
  **(find all notifications where recipient_id is Current_User)**
  def notifications
    @title = "Notifications"
    @activities = PublicActivity::Activity.order("created_at desc").where(recipient_id: current_user, recipient_type: "User") 
    @user = User.find_by_username(params[:id])
    render 'notifications'
  end
  </code></pre>
  
  <p>Is there a way to combine them so that the first method (activities) finds all activities EXCEPT those found in method 2(notifications) where a recipient_id equals current_user</p>
  
  <p>I know this is pretty easy to do....i just cant figure it out. Please help....New to Rails :D</p>
  
  <p>My current DB looks/stores everything like this</p>
  
  <pre><code>#&lt;PublicActivity::Activity id: 108, trackable_id: 133, trackable_type: "Relationship",
  owner_id: 1, owner_type: "User", key: "relationship.create", parameters: {}, 
  recipient_id: 1, recipient_type: User, created_at: "2013-06-16 07:37:28", 
  updated_at: "2013-06-16 07:37:28"&gt;
  </code></pre>