When this gem is loaded and activated inside your rails app, your MySQL connection adapter for ActiveRecord will be monkey-patched. The patch simply tweaks it to store all boolean "true" values as negative one instead of positive one inside your TINYINT columns. It also patches it to recognize and interpret negative one as "true". Positive one will still be recognized as true as well. Used for special cases, such as developing rails apps that must, for example, work with existing databases that use such a convention. For a rails app version X.Y.Z, use army-negative version "~> X.Y.0". For example, a rails 3.0.x app should use "~> 3.0.0" and a 3.1.x app would use "~> 3.1.0", etc. The exception is that rails 2.3.x apps should just use "~> 2.0" since 2.3 is the earliest version of rails that's supported.