Suggest/make additional changes at the end of the tutorial

[treyhunner]

Ideas:

• Allow posts to be drafted and only visible once they're "published"
• Limit the number of posts on the homepage (limit # of posts on homepage #11)
• Use friendly slug-based URLs (Use friendly URLs: year-month-day/blog-title-slug #12)
• Show post history in sidebar (Move post history on sidebar #10)