Kill trailing whitespace in ruby files

app/helpers/advertisements_helper.rb

@@ -4,14 +4,14 @@ module AdvertisementsHelper
 	    @advertisement = Advertisement.find(:first, :conditions => ["ad_type = ? AND status = 'active'", ad_type], :order => "random()")
 	    if @advertisement
   	    content_tag(
-  	      "div", 
+  	      "div",
   	      link_to(
   	        image_tag(
-  	          @advertisement.image_url, 
-  	          :alt => "Advertisement", 
-  	          :width => @advertisement.width, 
+  	          @advertisement.image_url,
+  	          :alt => "Advertisement",
+  	          :width => @advertisement.width,
   	          :height => @advertisement.height
-  	        ), 
+  	        ),
   	        advertisement_hits_path(:advertisement_id => @advertisement.id),
   	        :method => :post
   	      ),
@@ -22,7 +22,7 @@ module AdvertisementsHelper
 			""
 		end
   end
-  
+
   def render_rss_advertisement(short_or_long, safe)
     if Danbooru.config.can_see_ads?(CurrentUser.user)
       if safe