@diverso,
When Google bot visits your page at this address:
http://www.designdiverso.comit indexes the content it gets. After that, it happens to visit this link
http://www.designdiverso.com/index.html and it thinks it is a different page. Bot indexes the content and now sees that content is the same. Sites with duplicated content are ranged lower in SERP.
What i told you to do is to get some knowledge on this. Search for a complete solution to this with help of .htaccess file.
You seem to ignore 
I don't mind that at all. If you are in rush, i'm sure there are many seo in-knows available locally.
There is a couch version of permanent redirects. More read here:
http://docs.couchcms.com/tags-reference/redirect.htmlReference for links:
http://docs.couchcms.com/tags-reference/link.htmlhttp://docs.couchcms.com/concepts/pretty-urls.htmlI strongly advise you to follow the tutorial or refresh it if you did.
http://docs.couchcms.com/tutorials.htmlLooks, you need to get back to basics and there is nothing wrong with that. Unless you want to end up
grasping the tops and leave roots in soil. As an example of such waste of resource is your removed slash in some arbitrary way and place. You were given an example of how to do it properly for the mentioned template.