End of Iteration 6

Finished migratating to Tags instead of categories. Still havn't allowed to edit or add tags. So there is not much change from user's prespective.

By using acts_as_taggable gem and moving away from Categories, I was able to delete so many lines of code. It is a good thing, " Less code, less chances of error" :)

The only problem, I am facing that I was not able to solve is deploying it in my production server. For some reason my database migratation fails in production server. It is looking for articles_tags table in production server, when I have table named tags_articles. It is working fine in my local system. I checked all my gem versions etc.