update README with ActiveModel::Naming note [ci skip]
update README with ActiveModel::Naming note [ci skip]

quarkstudio/enumerize,monfresh/enumerize,maurogeorge/enumerize,victor95pc/enumerize,hungrything/enumerize,tanraya/enumerize,tranvictor/enumerize,shaundunne/enumerize,brainspec/enumerize