better online user list

app/models/user.rb

@@ -39,8 +39,12 @@ class User < ActiveRecord::Base
     !!self.confirmed
   end
 
+  def self.seen(time)
+    # when you change this, change footer.html.erb as well?
+    User.where("last_seen >= ?", time.ago).order("last_seen, desc")
+  end
+
   def online?
-    # when you change this, change footer.html.erb as well!
     last_seen && last_seen > 2.minutes.ago
   end
 

app/views/layouts/_footer.html.erb

@@ -1,4 +1,4 @@
-<% users = User.select{|u| u.online?} %>
+<% users = User.seen(2.minutes) %>
 <div id="footer">
   <div id="online-users">
     <p>Users seen within the last two minutes: <%= users.length %></p>