How to add a link attachment to bugzilla

Learned this from my colleague Yoshi: upload a html file with content:
Now click on the attachment, the html will be loaded and redirect to your page. The href is added in case if redirect does not happen.

I was trying to add a url of one google doc as an attachment to bugzilla, but found it's not as easy as I thought. Firstly I pasted the url as an attachment, which bugzilla created a text file with mime type "text/plain" initially, but click on the attachment doesn't redirect to the doc. I then tried different mime types for the text file: "text/url", "text/x-url", and "application/x-url" but none of them work.