Teach Rails Irregular Plurals with Inflections

English has plenty of irregular plurals. Criterion becomes criteria, not criterions. Rails handles many common ones already, but your domain might include words it doesn’t know about. Instead of… …accepting Rails’s best guess at a plural: "criterion" . pluralize #=> "criterions" "matrix" . pluralize #=> "matrices" # this one Rails knows! Use… … inflect.irregular to teach Rails the correct pair: #…