Moved that sidebar html into its own partial. Before the html was in posts/index, posts/show, and pages/about.
You probably already know this, but try to keep it DRY (don't repeat yourself). If you ever find yourself writing a lot of the same code repeatedly, it can probably be moved into its own partial, and you're less likely to have issues with it lately. (eg if you need to make a change, you don't have to go through changing multiple files and possibly forget one. Make it easy on your future self!)