Add since_id param to feeds

app/models/concerns/paginable.rb

@@ -2,6 +2,11 @@ module Paginable
   extend ActiveSupport::Concern
 
   included do
-    scope :paginate_by_max_id, -> (limit, max_id) { order('id desc').limit(limit).where(max_id.nil? ? '1=1' : ['id < ?', max_id]) }
+    def self.paginate_by_max_id(limit, max_id = nil, since_id = nil)
+      query = order('id desc').limit(limit)
+      query = query.where('id < ?', max_id) unless max_id.blank?
+      query = query.where('id > ?', since_id) unless since_id.blank?
+      query
+    end
   end
 end