♥ ASSALAMUALAIKUM ♥
Here the easy way to follow;
Go To Dashboard > Layout > Edit HTML 
Find code </head> (CTRL+F) 
Copy And paste code below above code </head> <script src="http://pinkdiva.googlecode.com/files/rainbowhoverlink.txt.txt" type="text/javascript"></script>
After the preview, and if there is no any errors. You may Save.
For Demo, you can click below text.
DEMO
Leave A Comment , Thank you! 😍
Note : All comments are moderated manually by real humans, so you won't see them appearing immediately.
For Non-Bloggers
Please select profile & click "Name/URL" If you do not have any profiles on any those listed. (Leave the URL empty).
It's harsh to call you Anonymous , So please Leave at least a Name.