A couple that I know of which are based on the security side of things are Brakeman (https://github.com/presidentbeef/brakeman https://github.com/presidentbeef/

A couple that I know of which are based on the security side of things are Brakeman (https://github.com/presidentbeef/brakeman https://github.com/presidentbeef/brakeman) and Scanny (https://github.com/openSUSE/scanny https://github.com/openSUSE/scanny) on the open source side. On the commercial side I know Checkmarx covers rails (http://www.checkmarx.com/ http://www.checkmarx.com/), amongst other languages