This project adapts the O'Reilly "Merb Mind Maps" post:

http://broadcast.oreilly.com/2009/02/merb-mind-maps.html

The do-list is now all about replacing that blog's convenient
assumptions with productization.

The project currently assumes:

 - your posts are called Post
 - your tags are called Tag
 - your association is post.tags
 - your Post title is .title
 - ActiveRecord (_not_ Sequel!)

Furtherless, BlogMindMap will rebuild the .png file on each page hit, and does not do the cute drop shadow.