I am about to create an application with Ruby on Rails and I would like to use multiple databases, basically is an accounting app that will have multiple companies for each user. I would like to **create a database for each company**

I found this post <http://programmerassist.com/article/302>
But I would like to read more thoughts about this issue.
I have to decide between MySQL and PosgreSQL, which database might fit better my problem.