Enforcing Ruby code quality

What you’ve just installed is a set of tools that check for duplicate code, complex code, code smells and code problems. The last one (metric-fu) will give you a report to look at if you need to browse for more details.

Next, you need to add some tasks to your rakefile. For my rails applications, I have this in lib/tasks/quality.rake, but you can put it anywhere that gets loaded by your build.
(Link: Enforcing Ruby code quality)