Automatically add ugoira tag to ugoira posts.

Note that this only adds the ugoira tag to .zip posts. It does not
remove the ugoira tag for posts converted from ugoira, but that aren't
true ugoira.

app/models/post.rb

@@ -562,14 +562,18 @@ class Post < ActiveRecord::Base
         tags << "huge_filesize"
       end
 
-      if file_ext == "swf"
+      if is_flash?
         tags << "flash"
       end
 
-      if file_ext == "webm"
+      if is_video?
         tags << "webm"
       end
 
+      if is_ugoira?
+        tags << "ugoira"
+      end
+
       return tags
     end
 

test/unit/post_test.rb

@@ -641,6 +641,42 @@ class PostTest < ActiveSupport::TestCase
         end
       end
 
+      context "with a .zip file extension" do
+        setup do
+          @post.file_ext = "zip"
+          @post.tag_string = ""
+          @post.save
+        end
+
+        should "have the appropriate file type tag added automatically" do
+          assert_match(/ugoira/, @post.tag_string)
+        end
+      end
+
+      context "with a .webm file extension" do
+        setup do
+          @post.file_ext = "webm"
+          @post.tag_string = ""
+          @post.save
+        end
+
+        should "have the appropriate file type tag added automatically" do
+          assert_match(/webm/, @post.tag_string)
+        end
+      end
+
+      context "with a .swf file extension" do
+        setup do
+          @post.file_ext = "swf"
+          @post.tag_string = ""
+          @post.save
+        end
+
+        should "have the appropriate file type tag added automatically" do
+          assert_match(/flash/, @post.tag_string)
+        end
+      end
+
       context "that has been updated" do
         should "create a new version if it's the first version" do
           assert_difference("PostVersion.count", 1) do