Upgrade to Mental? Need 'how to'

How can I upgrade an existing site to Mental?

I’ve tried copying the database from a working and successful 0.5.2 site
a svn export of Mental and running ‘rake db:migrate’

But when I access the site
a) The Markdown and Textile isn’t rendered
b) I get some SQL errors:


In preparing for battle I have always found that plans are useless, but
planning is indispensable.
Dwight D. Eisenhower