add ugoira support in view

app/models/pixiv_ugoira_frame_data.rb

@@ -1,4 +1,4 @@
 class PixivUgoiraFrameData < ActiveRecord::Base
-  attr_accessible :post_id, :data
+  attr_accessible :post_id, :data, :content_type
   serialize :data
 end

app/models/post.rb

@@ -138,7 +138,11 @@ class Post < ActiveRecord::Base
     end
 
     def is_video?
-      file_ext =~ /webm|zip/i
+      file_ext =~ /webm/i
+    end
+
+    def is_ugoira?
+      file_ext =~ /zip/i
     end
 
     def has_preview?