title: Mongodb: What to know before using?
body: <p>I'm starting a hobby (non-revenue) project using Ruby on Rails.  I've done a fair amount of development in Rails using Postgresql, and I can make a pretty good imitation of normalized schema.  However, Mongrodb looks shiny and new.  What better for trying out something new than a hobby project?</p>
  
  <p>Think back to when you started using Mongodb.  What techniques did you learn later that made you say, "If only I knew that when I started!"  What plug-ins did you discover that you would have used right from the start, if only you had known?  What references would you like to have had bookmarked?</p>